Canceled my contact and still getting invoices

Hi,

I canceled my contract in November due to the fact, I moved out from Germany. I sent a termination notice to the address provided here: 

I added all needed information - my abmeldung included. However, I am still getting the invoices. I thought it is a result of the 3-month penalty, but right now I have my own concerns.

I am no longer in Berlin as I am back in Poland from December. Can someone help me? I tried to reach you out through helpdesk, but the 45-minute long waiting time is a nightmare.

My customer number is: 606932XXXX

Thanks for help,
Daniel Wicher

edit o2_Matze please never post personal data, this is a public internet community