Vodacom Call Limit not working

I have a 2GB per month data contract which I have been using for the last 2 years, I have set a call Limit for R50 to avoid huge bills. But for the last 2 months I have been billed more than R1000 on my data contract which actual cost is R200/month.<br> <br> I phoned Vodacom and they said due to a slow system the call limit might only be activated a while later, I can understand that.<br> <br> But to use more than 500MB (R1000) in a while later is impossible especially if you only use your data for e-mails and a bit of internet research.<br> <br> So in other words the call limit does not work at all or a while later can be up to a week.<br> <br> I would like to be credited the amount used because the call limit did clearly not work. I do not get notifications as the simcard is in a wifi router.