Hello, I have DSL 24momths contract in Cologne. The contact started on January 2020. Since I move out of Germany permanently, I would like to cancel my contract. I'll go back to Japan in two weeks. Due to this pandemic situation, I can't go to city hall to deregister address. I sent them documents by email for deregister address but no response so I don't think I will get the certification of deregister from them.
All I can provide to O2 are the flight ticket which mentions going back to Japan and also Visa expires 13th February 2021. I'll stay in parents house in Japan so I can't provide renting contract in Japan.
I visited O2 shop to ask but the stuff just told me to ask online service. Could somebody tell me if flight ticket and visa are enough for cancellation? Or what do I need? I'm also renting router from them.
Thank you so much in advance