Canceled contract they took the phone but still debit money.

27 February 2023 decided to take a phone contract deal and the phone was delivered within 3 days soon after, around the 3rd of March 2023 I wasn't happy with the phone I took it back (the cooling off period has not ended ) so I did not expect some extra charges. To my surprise the cancelation has not been fully processed because they are still trying to debit money from my account but had already took the phone. I attempted to call them none of them is willing to help instead they are busy transferring the call until it hangs up , send emails but nothing still.