Account debited after manual payment

Telkom mobile debited my account on the 20th however the debit order bounced. I thought they will retry but I received an sms saying I should make payment. I then called the contact centre and was told to make a manual payment and they kindly gave me the account number and the reference for payment and I paid after that. Despite making payment I then receive a notification from my bank saying a debit order has gone off my account from Telkom. Now am just wondering is this how they rob their customers or is just a way of saying if there is a slip up with a debit they encourage you to just cancel your contract