Incorrect Billing

In the beginning of October 2014 I received a message saying I have used R3000 worth of data. I immediately called Altech autopage to inquire what the R3000 bill was for and they told me to complete a form for a usage report from Vodacom. Till this date after numerous calls and emails to Altech regarding this usage report I am told today that they cannot supply me with the report and neither can the service provider. I refuse to pay for something I don't have proof I used. Altech has now blacklisted my name and I would like answers as to why I cannot get a usage report. This bill has now gone to R5000 due to interest and I refuse to pay until Vodacom shows me what I used this R3000 on. This service I have received from Altech is pathetic and disgusting for such a huge company. It seems they do not have proof I used that much data that is why they are giving me the run around.