Ridiculous Billing

I've been with Nashua Mobile for more than 10 years and now Autopage took over Nashua Mobile. I never had a problem with Nashua regarding billing but with Autopage I really have very high billing that is impossible. During the day on Wifi and on most of the billing is during that day when my mobile data was off.<br> Randomly data unauthorized almost more than 2G that I'm billed for and also when I had a problem in September as well regarding this matter and requested a limit. When my data is finished my phone is useless it goes off completely everyday I check my balance to see if I'm not in arrears. Since I received a bill or R770.88 (Because of accident) I started using my data and calls wisely. September Month I also had a problem customer care said that my data was finished and then when I requested my balance on phone it showed I had data on my phone, so they corrected it. Every time phone into customer care and start to question my balance then the phone gets dropped and I have to call in again! It happened today as well (22 Oct 2015). My contract is R355 per month.. My statement is R925.05 that is R376.84 data? How is this possible? And now that I query my data get switched off