Fed up of Showmax

I've cancelled my Showmax Account few months ago. They've keep on debited my account. I went back and forth with them, even sént them bank statements, the mail they've sent me indicating my account was cancelled but nothing. For this month alone they tried to debit my account almost 5 times. Luckily I didn't keep money in my main account, because I knew they always trg to debit my account. I can't even sign in on my account, because I don't have an account anymore, which indicates my account has been cancelled. So why do they still try to debit. I'm now fed up of sending mails every month to explain my situation. Please help their service is pathetic.