Can’t get membership cancelled and account debited each month with increased fees

My contract came to an end in lockdown. I emailed them when I saw their debit order still going off and suddenly also R150 increased price on previous amount. They send me a mail saying due to lockdown my contract ends October and then it’s month to month. I again said I cancelled my contract I am not interested in continuing with them. They just keep on debiting my account and not even my bank can stop the debit orders. It’s just ridiculous that you don’t have any control over these deductions.