They are billing me for data while having a bundle

Last month I received a bill of R1766.59 from Vodacom because of data that I apparently used (out of bundle rates), but I did buy extra bundles as soon as it ran out, that never came through and most of it happened while I was asleep. (My apps only update on wifi btw)<br> <br> Currently (3 September) my bill is standing on R1391.44 (in counting), while I still have 799.11MB left on my data bundle. I called Vodacom customer care twice about this query, but they cannot help me. What do I do??<br> <br> (I have a Smart S contract with Vodacom with extra data of 1GB)