Disputing a mobile bill in Switzerland: how to challenge incorrect charges

An unexpectedly high mobile bill can have many causes: data roaming abroad, a paid premium service, an option that was charged incorrectly or uncertainties following a contract change. It is important not to rely only on a phone call. If you want to dispute a mobile bill, you should document the case, challenge it in writing and set the provider a clear deadline.

This guide shows you the correct order of steps. It applies whether the issue concerns a few francs or a high subsequent charge.

First check: what exactly was charged?

Download the itemised bill and compare it with the documents relating to your subscription. A high total alone is not enough for a dispute: you need to identify as precisely as possible which item you are challenging and why.

Pay particular attention to these bill items:

• Basic fee and discounts: was the agreed promotional price or an existing discount applied correctly?
• Mobile data in Switzerland: are additional packages, data options or excess usage listed that you did not order?
• Roaming: check the country, period, data volume, calls and SMS. Costs often arise from mobile data even if you barely used the phone actively.
• Premium services: these services can be billed via SMS, short codes or a charge on the phone bill. They do not necessarily come from the mobile provider itself.
• One-off fees: check activation, change, device, reminder or cancellation fees.
• Contract changes: following a subscription change, the billing period, discounts or included services may change.

Compare the bill with your order confirmation, contract and any emails concerning the contract change. If you want to reassess your subscription or the services included, the mobile overview offers general comparison options.

Which evidence should you secure before disputing the bill?

Secure all documents before contacting the provider. Consumption data, bills or option details in the customer portal may later change or only remain available for a limited time.

Ideally, create a folder containing the following documents:

• the complete bill as a PDF or screenshot
• itemised call records and detailed consumption data, where available
• contract, order confirmation and information about discounts or options
• screenshots from the customer portal, especially relating to roaming packages and data usage
• SMS, emails or push notifications about activated services, limits or cost warnings
• travel documents if you dispute roaming charges, for example because the wrong country was assigned
• notes about phone calls: date, contact person’s name and promised solution

For a suspected unauthorised premium service, the service name, short code, date and amount are particularly important. Do not delete the relevant SMS messages. They may show when and how a service was activated.

How to classify the three most common disputes

Roaming charges: check usage, package and country zone

Roaming bills are often understandable, but not always correct. First check whether the country you visited was included in your roaming package zone. Some offers apply only in certain European countries or exclude individual areas.

Also clarify these questions:

• Was data roaming enabled on the device?
• Was a data package activated before or only after the usage occurred?
• Had the package expired, or had the data volume been used up?
• Did your device connect to a foreign network even though you were near the Swiss border?
• Does the bill concern data, outgoing calls or incoming calls?

If you dispute the charges, request a comprehensible breakdown showing the date, time, network, country and billed service. Do not merely say that the bill is too high. Explain specifically why, in your view, the charge does not match the contract, travel period or settings on your device.

Premium services: identify the provider and block the service

Premium services are additional services that can be collected through the mobile bill. They may include subscription content, SMS services or purchases charged to the mobile bill. They are often recognisable as a separate item or short code.

First dispute the charge in writing with your mobile provider and request an explanation. With premium services, the service provider may also be relevant. The ombudsman’s website provides information on the procedure for a dispute concerning premium services.

At the same time, request that the relevant service be deactivated. You can also ask your mobile provider to block premium services or certain categories in the future. Have the block confirmed in writing.

Contract and billing disputes: give priority to the agreement

If a discount was not applied, a cancellation was ignored or an option continued to be billed despite revocation, your contract documents are decisive. Enclose the relevant passage and state when you made the change, cancellation or order.

For a cancellation, timely dispatch and proof of delivery are particularly valuable. For online cancellations, a confirmation email, screenshot of the form and ticket number can help.

How to formulate your written dispute

A phone call can be helpful, but it does not replace a documented dispute. Submit your dispute through the provider’s written support channel, such as a contact form, email, customer portal or registered letter. Keep a copy and proof of dispatch.

Your letter should be short, factual and unambiguous:

> Subject: dispute of mobile bill dated [date], customer number [number]

>

> Dear Sir or Madam,

>

> I dispute the item [exact description] amounting to CHF [amount] on the bill dated [date]. After reviewing it, I cannot understand this charge for the following reason: [specific explanation].

>

> Please send me an itemised statement by [date, for example within 14 days] and correct the bill or credit the disputed amount if the charge cannot be substantiated.

>

> I will pay the undisputed bill items on time. Please confirm receipt of my dispute in writing and let me know how you will handle the disputed amount until the matter is resolved.

>

> Yours faithfully

Set a realistic deadline, usually 14 days. The provider may need more time in complex cases. What matters is that you request a written response or at least comprehensible interim information.

Should you pay the bill in full?

Do not ignore the bill. This can lead to reminders, collection costs or, in the worst case, suspension. If only individual items are disputed, it is generally sensible to pay the undisputed amount on time and clearly identify the disputed amount.

Whether you can temporarily withhold the disputed part or should pay it under reservation depends on the individual case and the contractual conditions. Therefore, ask the provider in writing to confirm that it will not take reminder or suspension measures for the disputed portion while it investigates. In the case of a high claim or an announced debt-enforcement proceeding, independent legal advice may be useful.

If the provider does not cooperate: contact Ombudscom

Ombudscom is the conciliation body for disputes in the telecommunications sector. It can support an out-of-court agreement between customers and telecommunications service providers. Before initiating proceedings, you generally have to try to resolve the conflict directly with the provider first.

The Federal Office of Communications explains when you can contact Ombudscom. It is also important to note that Ombudscom does not replace a court and cannot make a binding decision in every dispute. It first checks whether the requirements for conciliation proceedings are met.

For an application, include at least:

• your written dispute to the provider
• the provider’s response or proof that no sufficient response was received
• bill, contract and relevant evidence
• a clear description of your request, such as a correction, credit or itemised statement

You can find further information about the procedure from OFCOM under conciliation in the telecommunications sector.

When another body may be responsible

Not every dispute falls within Ombudscom’s remit. If you suspect fraud, identity misuse or use of an account or SIM that you did not authorise, you should also promptly inform your provider and consider reporting the matter to the police.

If the issue primarily concerns contract law, debt collection or debt enforcement, a cantonal consumer advice service, legal advice or a court may be more appropriate depending on the situation. Ombudscom is primarily intended for disputes concerning telecommunications services and their billing.

Checklist: disputing a mobile bill in Switzerland

1. Download the bill and itemised call records immediately.
2. Mark disputed items by amount, date and type of service.
3. Save the contract, orders, SMS messages and screenshots.
4. Contact the provider in writing and set a clear deadline.
5. Pay undisputed parts of the bill on time.
6. For premium services, request a block and clarify who provides the service.
7. If no workable solution is found, contact Ombudscom with complete documentation.

A precise, well-documented dispute significantly increases the chance of a quick resolution. Afterwards, also check your current options, roaming settings and premium-service blocks. You can find general decision-making assistance in our guide section and at the mobile comparison.