MTN contract cancellation struggle

I advise people to never take up a contract deal with MTN no matter how sweet the deal is, I took up a 2 year data plan contract with them back in 2019, as soon as it was active, my rates went through the roof, R10 Airtime was equivalent to 2min. The 24months is now over, I've call them a thousand times to cancel and I'm told it will be cancelled and I'm given a reference number (it means absolutely nothing it's useless) but they still take money from my account come the debit date. I went in one of they're store to pay whatever they said I owed them, but they still took money from my account and included that very same amount I paid. MTN is really robbing they're clients, and they're customer service are very poor, you wait for a long time before you get assistance from they're call centre, and every time you're given a different story from the last and are told your contract is still active and on a month to month basis, but tried cancelling a million times