Packet Switched Data

I have a top up contract with MTN - in order to avoid a surprise at the end of the month. Had no problems, my bill amount is always the same, about R398 a month. From July it started increasing to about R600.<br> Doesnt help to send an email. I thought ok, they increased their tariffs, just leave it at that.<br> This month I received a bill of over R2600. I have been trying to sort this out, everyone at the call centre tells me a different story or gives me different numbers to dial.<br> One lady even told me that since the strike there has been a lot of issues with billling.<br> Now I get told my huge amount is due to Packet Switched Data calls. Does this have anything to do with the fact that I recently added a data bundle - in order to prevent problems?????<br> There's no way I can afford such a hefty bill.<br> Why should you put a limit on your contract if you have a top up contract???