ADT *****ing money from account

After cancelling ADT services in November 2022 they since stole from my account 3 times, and now I receive an account to be paid by end of January. They refuse to stop my debit order as the bank cannot do it and every timer I reverse it ADT change the code on their side and keep *****ing from me. They also refused to send me a cancellation form and told me via a phone call they cancelled my contract - but yet they keep on *****ing money from my account