I send my request for contract termination in August 2016 as at 31 October 2016 as I was going to leave Germany. It was confirmed, I left Germany thinking I have paid all my invoices on time and sent the router back. 



However, almost half year later, I keep receiving monthly invoices and Mahnungen and in no way I can reach someone from O2 who can help me solve the problem. The hotline is impossible, in the chat they told me to just send a letter, because the termination is confirmed but it did not "go through their system yet" ?!? What should that mean, they confirmed to me that everything is ok, but they still send me invoices for something I don;t use and I terminated dully in advance!!! I sent a letter to O2, but it has been more than a month with no progress, and the invoices keep coming. 



This is a nightmare and I hope here I can reach someone who can help me be over with it.