Cancelation of O2 broadband connection

I have ordered an O2 home connection in december 2023 to my new home in ulm. A week after that I changed my mind and went to the O2 shop for cancelation. They told me the request fpr cancelation has been sent and meanwhile if you get the fritzbox donot accept it so that it will  automatically return. I have done the same. So I neither collected the fritzbox nor the connection. But by February they started auto debiting money from my bank account. I tried calling the help line and they told me I have to go to the shop from where I got the contract. I went to the shop again and they told me only the hot line could cancel it. When I called the hot line they sent me this english community link. I need to cancel the contract and get a full refund of the money. Its like Iam paying for something I didn‘t even use or got.