Being Billed Incorrectly

I have a Telkom/8ta contract for about a year and a half and this is the second I've been billed incorrectly. On the 9th of January I made a manual payment of R598 at the bank, which reflected on the 12th of January on my account. On the morning of the 16th of January I receieved an sms from my bank, stating that Telkom had debited R898 from my bank account. I immediately called 081180 and spoke to a girl who's name is Lesedi (I cannot recall her surname) and she was very rude to me. Not at all professional. Later, in the afternoon, I called again and I spoke to Lunga Klaas. He was very helpful and understoood my situation, because the debit order was not supposed to go off at all. I was not even supposed to pay R898. He told me that it would all be sorted. I waited and waited for a phone call, but received none. I even sent him an email with proof of the debit payment having gone off my account and I asked him to acknowledge receipt of the email - yet I'm still waiting for the email. I then had to make a third phone call which resulted with me getting a case number (***8) and a promise that I'll get an answer 72 hours, that ended yesterday. I'm still waiting!!!!