JUST DROP THE PHONE

Since April I have queried my data just disappearing into thin air. I have 2G contract but now it shows and then it shows I have used it all. I use computer daily to check emails and read newspaper. It never was a problem and what was left on that month I would download a movie in order to not lose the facility. Now I NEVER have data and even when I purchase 1G its gone the very next day. MTN is not responding to my complaint and I do not know what is happening. I can not have a contract and purchase cash. Totally unacceptable. When I phone call centre consultant just drop phone if they cant help. NO ASSISTANCE FROM MTN..