Wrong billing and debit order faults

I have always been an ambassador for Telkom Mobile. I have been with Telkom for YEARS, not a single problem. In December I received an account for about R300 worth of SMS sent, that I DID NOT SEND. I mean, who, in the 21st century sends R300's sms, when you get 50 free PER DAY!? Anyway, I tried to dispute it, before the debit order goes off, but I need the invoice, you only get AFTER the debit order went through. So I thought I'd dispute it afterwards. Suprise! I received an sms saying that my debit order did not go off, and now have to pay a penalty fee as well. But my bankstatement cleary shows the debit order that went off and was paid in full. How on earth do they get that right? Now I still don't have an invoice and have MORE to dispute!