Telkom double debit

Back in Aug, I changed my debit order date from 28th to 1st of the month. I was told that it would only be effective as of 01 Oct.

On 28 Aug, Telkom debited my account and it bounced. Upon noticing this, I transferred money into that account and they successfully debited the funds on 30 Aug.

And then comes 14 Sept, Telkom tried to debit my account again. This included the "arrears" amount as well as what is due at the end of September! I called the call center and was on the phone for 14 mins until it eventually cut off.

This is not the service i signed up for.