Horrible customer service

I have a contract with Telkom of which the debit order goes through on the 25th of every month, to my surprise I was not debited on the month of March and again this month of April, when I called them on the 26th April to ask why, the consulted informed me that they might debit later on that day but nothing happened and she told me that my account has been handed over to debt collectors which was very surprising as I always have funds enough in my account, I asked her as to why was I not informed about my account being handed over to debt collectors prior, then the lady just hangup on me when I paused those questions to her, where can one get answers if not from your consultant? This was a horrible experience ever. Why was the deduction made on the agreed date? Why do you hand my account although it's your fault that you did not debit.