Two contracts instead of one - one unknown phone number

Hello, 
I placed an order with O2 for one mobile line, but on my invoice I noticed that two contracts/two phone numbers were opened. I don’t have the SIM card for one of them, and I don’t recognize it at all.

I contacted the shop where i placed the order, but I was told the contract cannot be cancelled. I would like to know:

1. How can I verify/confirm which products I acutally ordered?
2. How can I request cancellation of the contract I did not order?
3. Who should I contact within O2 specifically for this issue (not the shop)?

Thank you in advance

Edit: Thread moved to our english community, o2 Michi 25.07.2026