SYSTEMS OFFLINE/OVERCHARGED ON DATA

I use the MyMTN app to monitor my data usage as I was once charged for an exorbitant amount. For the past few weeks I have not been able to get onto the Mymtn app to see what my available data was on my wifi rooter. I have been getting an error saying that the server is unavailable and I must try later. I always carry data over as I do not use the entire amount I am given in my package. This week I decided to call the call centre to find out what my balance is I cannot get this on the app and I am told I have gone over the allowed gb. How convenient for them, the whole month I cannot get onto the app to check my balance and conveniently they charged me as I went over which I don't believe!! I am so sick of this service provider. My wifi contract is up in November and my cellphone in October. I am MOST DEFINITELY cancelling both with them. <br> On my cellphone I NEVER have signal - I am beyond sick of them.