Cancelation of old contract after the purchase of new did not happen-stop stealing from me

On 4th of January this year I called the customer service to request the cancelation of my old contract (o2 Blue All-in L) which I have since 2014. This was before the three months required period for cancelation. The reason for cancelling that contract is that it is too expensive compared to the services offered.

The customer support employee offered me a solution and suggested to me to get a new contract which had a much better offer for almost half of the price. Since I was until that point satisfied with O2 I accepted the offer and I ordered a new contract (O2 Free M Partnerkarte mit 20 GB) with a new number and sim card. In the same phone-call I asked about five-six times if my old contract will be canceled now and if I have to take further actions for this cancelation. The employee confirmed to me that I do not have to do anything else and that my old contract will be canceled in the end of the three month period. I received the email for the telephone order and latter the new sim card to my current address. 

Luckily I have a witness for this as my flatmate was the whole time there listening to the call. 

Three months later I realise that my old contract was automatically prolonged for one year!!!! Now I am being charged with two contracts. I have spent countless hours since then trying to figure this out with the customer service on the phone. A ticket was sent in April from one of the employees for the cancelation. O2 sent the answer for that ticket to a house where I lived four years ago (as opposed to sending the new SIM card to the correct address). Luckily I called again, they told me that the answer to the first ticket was negative (although I never received it). Then, another employee sent a second ticket, which as I found out later was not even considered sinse the answer to the first ticket was sent to the wrong address!!!! Yesterday I was told by the customer support that they sent me again the answer for the first ticket as an answer for the second ticket on 5th of May signed from a Sachbearbeiterin I. Boetig. This letter refused the cancelation of any of the two contracts. 

Thus this person I. Boetig decided that O2 has the right to steal money from me every month for the contract o2 Blue All-in L which should have been canceled. 

This is a clear scam and it is unbelievable that you treat an old customer like this. 

In my last phone call to the customer service yesterday I asked for the name of the employee that sold me the new (O2 Free M Partnerkarte mit 20 GB) contract and a record of that call where the cancelation of the old contract was confirmed including that I don’t have to do anything more. They told me that they are not allowed to provide this information. 

O2 is recording all the calls!!! You have the proof right there that I was scammed. Or do you only do this recordings to train your personnel on how to scam english speaking customers in a more effective way?!!!!

I want my old contract o2 Blue All-in L to be canceled immediately and my money that I paid for this for since the end of the contract which should have been 05.04.2021.

STOP STEALING FROM ME