Bill incorrect

Hi, hopefully I have posted in the correct spot for the English Community

I signed up for a DSL contract in January. The man at the shop gave me a SIM card to use while I waited for the activation by Telekom. He had said that this was only valid for one month and the data is only 1GB. No additional contract was signed besides my DSL contract.

I looked at my bank account yesterday and saw there was additional charges from o2 in January, Feb, and now March. This is for a 1GB SIM card contract that I have never signed.

I have the original Kundenauftrag and it makes no mention of a further 1GB SIM card contract. I would like the charges to be removed and also receive the money I paid for these months.

Danke für deine Hilfe