Ridiculous Billing Charges

I canceled my Mweb 2GB R128pm mobile Subscription in August giving them 1 months notice as requested and according to Mweb my subscription would be canceled the end of September, End of September came and I received a bill for R1500, after contacting mweb they said i exceeded my limit which is strange since i have a R100 Soft CAP to stop this from happening but according to Mweb this did not kick in, very strange that this would happen suddenly after canceling my contract with Mweb. The response i got from Mweb is that they don't guarantee the soft CAP and i must look after my own Data Usage which i find to be BullSh#t. Just how many people are they steeling money from this way and giving them the same poor excuse.. My CAP has always worked for the past 24Months and now all of a sudden it doesn't work.... And now to put the cherry on top I receive another Bill from Mweb for R480 for October usage, How is this even possible if i couldn't even use the Sim Card as it was canceled. I find your Billing department absolutely useless in resolving these matters a 24hour to 48hour turn around time is pathetic, please sort this out #PayBackTheMoney