Data Card

I have a data card on contract with Vodacom. It has a limit if R250 set on the account. My last 3 bills have however varied between R600 to R900. I called into the call center and they said I must have been continuously connected for a long period and hence the limit did not kick in. I asked that I be provided my detailed bill so that I may see the the connection time. I was sent 3 invoices with only the rand amount of the bill. No other detail was provided.