MTN contract not cancelled and keep billing my account

I had a data only sim contract with MTN it was a 2 year contract and it was due to expire 26.07.2023 and I cancelled a month prior as it was to expire. But on the 27th of July i discovered it wasn’t cancelled and I have been calling almost everyday and sending emails regarding this cancellation and it has not been done and there has been no way forward but I’m still being billed. I was even billed more than the usual installment I was paying for contract. No one from MTN has contacted me with a solution I keep being told my query has been escalated but with no results. I’m a tired now, this is a **** MTN is being unfair.