Grossly overcharged for data & no idea why!

I have been grossly overcharged for data this last month, and I have been trying since the 9th July to get to the bottom of it - must have called the call centre 150 times by now, without success.<br> <br> I have a feeling I didn't receive my data bundles and have been charged accordingly - which is WRONG!<br> <br> The one and only time I got through to a call centre agent, she told me that my bill was sitting at around R2k for data, but I still had 1.2 gigs of data available. Please explain to me how on earth that is possible? Doesn't make any sense.<br> <br> My bill has been under R800 pe month since I got my new contract last year, and this month they want to charge me close to R3k when I've done nothing different. I want someone to call me and explain what is going on, and FIX THE PROBLEM so my bill is normal, or I am cancelling my contract.