STILL DEBITS BUT INSURANCE WAS CANCELLED.

I am highly unimpressed with budget who debited my account today while my insurance with them was cancelled. They never even debited on this date when I was a client. I specifically asked when I cancelled whether a debit would still go through and I was advised NO, but yet today a debit went through. I've stopped the debit order on my app in order to avoid any future unauthorized debit orders but unfortunately this was went through and due to their incompetence I can't not even reverse the money back as this could potentially have a negative effect on my credit score eventhough it wasn't supposed to have been charged.