Deduct subscription after cancelation

I took out a contract few years ago for my fatherin law, when the contract ended it was a month to month subscription. When he passed on, I phoned one2one, the consultant said only an email was required to cancel. On the 10th of October 2022 I send the email. The subscription kept on deducting from my account. I phoned again, and a very rude lady, Shannor Sharlinck said I was supposed to confirm with another email..not as agreed upon as one2one advised me. Last month July 2023, the subscription was canceled. 8 months of paying for a service not used?? I consider that as total theft from a pensioner