Billing frustrations

Oct 2020, went to the store to change my banking details (to debit ) however it was never actioned. They continued to debit on the wrong account until December2020 I reversed the amount and made a manual payment and requested again to debit on the new account which I sent the information back in Oct. They have not updated the new account as they still have not debited, I have spoken to more the 10 consultants and they keep on saying they will escalate my query. I don't think I am going to renew my contract with them as I am due for an upgrade within the next months ( I am exhausted )