After account limit request still receive R6k bill

After an incident where vodacom charged us for data usage of over R 8,000.00 in 2014, which we had to pay, and they had no means of proving that we used it, we specifically asked for them to limit our lines. Our contract terms and conditions state that each line will be limited to credit score availability.<br> We have once again received a bill on 1 line for R 6,500.00.<br> After phoning vodacom and asking them how this is possible as we asked for the line to be limited, they said that they don't do that and it is our fault that we received such a massive bill.<br> We then asked them what about the limit by credit, and they said that all of our lines are limited together for R 4,000.00. If we take all of our lines in to account the total bill is R 7,500.00. How did they then even limit on R4,000.00? They specifically stated that all the lines' limits are grouped into one account, which is the R4,000.00.<br> This is completely unacceptable, and we refuse to pay this account as we specifically asked for the lines to be soft locked by vodacom to avoid the recurrence of the 2014 issue.