Telkom Still Debiting after Account has been Closed

I cancelled my account with Telkom on the 24th of May 2018 and I am still being debited even though I have confirmed that my account was indeed closed.

I have received an invoice charging me around 3 - 4 times the amount I was initially paying.

DO NOT DEAL WITH TELKOM OR IF YOU DO, DO NOT ALLOW A DEBIT ORDER WHEN YOU SIGN UP.