Taking unauthorized money off my account

I had a contract that came to an end in November 2023, I went to the branch in October 2023 to cancel the contract, they still debit my account, from my side I then stopped the amount from going off which then they decreased the amount still taking money off my account and phoned that I am in arrears. I literally sent them the paperwork that I signed to cancel the contract and the time I was at the branch to cancel the contract, but I see once again that they have taken money off my account. So what is it going to take to leave me alone and to refund my funds???? Must I physically come and destroy your head office? Don't tempt me!!!!