Overcharged on My Account Without Warning

I was overcharged by MTN this month (R1 300).<br> <br> Whenever I use much data or talk time on my mobile phone, I receive a warning SMS that I have reached 90% of my account (my account is capped at R629 each month which includes SMS, talk time and data). If I continue to use my phone then my account is suspended. I then have to call MTN to ask to have it re-opened. Some time ago, my account was suspended and the agent I spoke to at the time said specifically that it was due to my data usage.<br> <br> This time around (during May 2015), I received no warning SMS and my account was never suspended. However, they charged me in excess of R1 300. The call centre agent I spoke to said that I am on an \Anytime"contract which means my talk time is limited but my data has no limit so they allowed me to continue to use data. He also said that I receive a warning SMS when I use 50% of my account for the month. I have never received such an SMS.<br> <br> There is no point trying to argue with him because he repeats what he reads on his computer and his manager/supervisor is on strike. I've sent an email to their Customer Care and am awaiting a response."""