Debit order disputes

I cancelled a contract with them and received a confirmation that it was cancelled but they keep debiting my account on any given date was on 21st and again on 31st of October. I paid up until the cancellation date and the next month because they always say it’s late notice so I paid the following month but the debits won’t stop and my bank won’t allow me to reverse the payment. It’s not right that I should pay for a service I don’t have or use when trying to call u never get through but their consultants won’t have a clue even if they answer