Shocking bad service

I have been struggling with my contract cancellation. In OCT 2022 I sent an email notice to cancel my contract. I received an email Dec 15th confirming cancellation. What is disappointing is it took them 2 MONTHS TO RESPOND. Agents communicated to me that they cannot cancel contracts telephonically.

Alas they kept deducting my account. I've had to keep cancelling. Now i keep receiving calls from their collections team. I even forwarded an email of the cancellation to an agent that called last week who had promised to share the email with accounts. Today I received another call from collections. I hate reversing debit orders as it has a negative impact on my credit score. No one seems to care about fixing this.