Ridiculous Data Usage

I always check my data balance and make sure i dont run out of data knowing that the out of bundle charges is ridiculous. I went on to the My Vodacom App this morning only to find that my account jumped from R2206 to R13457.23 overnight. What they are telling me is that on the night of the 31st and the morning of the 1st i was doing excessive Googling and whatnot. But if you look at my cellphones Cellular Data Usage Summary it shows that from the 21st December up until today i have used approximately 829 MB. Now lets say that 829 MB was out of bundle even though it wasnt. That would cost me R1658 @ R2 per/MB. I did not recieve any messages telling me that my data is running out or that my data has run out. I am waiting for a response from dataportal to see what the data was for but either way it won't bring down my account. I had the same problem exactly two years ago on the same night apparently and the account was R12000 but that i paid as i was not aware of out of bundle rates. Please help me guys I am going to Cancel my Vodacom Contracts and I know i am a loyal Vodacom customer since the 90's. My other Company is JFC Construction. Both is rated as VIP Clients Thanks.