Bad service

I have cancelled my contract on the 5th November 2025 and they asked me to complete a cancellation form on the 13th November 2025, which I did that the same day. Someone from Capital called mid January 2026 promising they will fix the issue and reverse my debit order for December 2025. I noticed Capital is still deducting premiums on my account. I just want to cancel the contract even if they don't return my funds which were not due to them