Data Missing. Useless Support

I have a 40gig contract and every month i only use about 20gig. Last month the 40gig was depleted before the 20th. I have been fighting with Telkom and not received any honest response. All I get is a auto reply saying there is no unusual activity, After about 10 emails i got a human response Then I am told even if they did find unusual activity they would not refund any data anyway. They told me to monitor use carefully this month which I did. On Friday I still had 20gig left. On Sunday I am suddenly out of Data. The ladies at the telkom shop were a great help and showed me where there was no internet activity but data was used. The lady at the online chat sent me an excel spread sheet showing unusual data use. But the useless Technical support cannot see anything.