Left Germany and cancelled my contract - Now I got an new automatically sent new tariff

I left Germany for good a month ago and cancelled all my contracts with all the required documents.

Today, I got a new automated email saying that I now have a new tariff that I will have to pay for. Since o2 prides itself of not having any customer service for it’s users, I thought I would write here and see if anyone here can assist. 

What should I do here? Should I go straight to the laywers and let them deal with it, or should I just use this forum here to communicate?

I would have sent an email, but naturally o2 doesn’t have one to contact them with. As I now live in Thailand and calling to o2 to sit in queue for 45min at a cost of 10€ per minute + whatever scam rate o2 has to call them at all isn’t something I would do. 

Looking forward to your reply. 

Edit o2_Cora 18.02.24: Post moved from → O₂ Mobilfunk: Vertrag & Tarife