Unauthorised debit

I contacted them on 26 June 2026 to cancel my device insurance, I received confirmation that this was cancelled and no future debits will go off my account. To my surprise, my account was debited on 25 August. I immediately contacted them to query this debit and I was requested to send a tax invoice (which is something they should have in their possession) I sent the required invoice and now I’m informed that I was not removed from the billing and they can only refund me end of September (I MUST STILL CALL THEM) after their billing cycle has ended. My bank unfortunately can also not reverse this due to a “BLOCKAGE” from MTN…I am disgusted by the level of service received!