How to cancel Second SIM Contract with O2

Hello fellow O2 community members,

I've been an O2 customer since December 2021 and recently discovered that I've been charged for a second SIM that I haven't been using for the past two years. Although I've extended the contract for my main SIM, I want to cancel the second SIM, as I don't even know its whereabouts and haven't used it.

I've tried navigating through "Meine O2" online, but I'm only finding options to extend the contract for the second SIM. Can anyone guide me on how to cancel the contract for the unused SIM online? Your assistance would be greatly appreciated.

Thank you in advance!

27.10.2023 15:51 o2_Katja: verschoben aus Mobilfunkvertrag