Failure to terminate contract even after the customer provided a a calendar month notice

Flight club is refusing to cancel our 12 months contracts . We have communicated 30 days before the contract ends that we won’t be extending They later sent us an email that they are not in the office due to covid19 and therefore can’t action the request. But still they continue to debit our account inspire the fact that the contract ended in May There were additional R99 which the processed now in August they debit R1072 * 2 post the email comms sent in July that we require an email confirming that this contract is terminated. We requested they stop sending us email comms on any bookings or correspondence as we are not interested in renewing our contract. It’s not my problem that they could not operate during lockdown and that does not grant them to extend our contract for the months they where not operating