Bad service

I cancelled my mtn contract in October 2021. Everything seemed sorted. The debit order did not go off in November. I assumed contract was cancelled. To my disbelief a debit order went off in December. I asked the consultant for the exact amount that I must pay to cancel. I paid it and emailed proof of payment to her. I reversed that debit order today. Terrible unprofessional service from mtn. A company that I supported for over ten years