Insane invoice amount

In May 2015, I received a wonderful account from MTN, to the sum of R12,000<br> How is this possible, my average consumption for the past 12 months have never exceeded R2,000 - R2,500.<br> I am very fami**** with how Data works, and thus monitor my usage carefully, I do go over my allocated bundle often, and load additional bundles as soon as this is noticed. I control downloads and know what is updating or downloading at any given time<br> <br> However, this month for some reason, I apparently exceeded my bundle by close to R9,000 on out of bundle usage. I queried this with accounts, asking for an audit, but received no response. I phoned MTN, but apparently the call centers are closed.<br> <br> What I find very weird is that I was not even home for two of the four weeks of May, being away on business. I do not have Wifi active on my router, no one else has access to the router in the locked up house. SO!, how is it possible to have not only doubled my normal usage, but quadrupled it?<br> <br> I have tried every possible way to contact them, so I guess I am **** out of luck. <br>