MTN *****ing my data and ****py network

My data keeps vanishing I loaded 350mb yesterday, this morning I had 200mb left, I check at 11am I was on 115mb I check now at 12 and I'm on 13kb. I need to know what happened to my data because when I'm not chatting my data is off. Can someone call me to explain what happened. This has been going on for a while but its enough now. I would also like to know when my contract is expiring so I can port because I have asked numerous times for a network booster in my area but nothing has been done and as a result someone was fiddling with my car at night and tracker couldn't get hold of me because of the ****py network. I have had contacts with MTN forever but they cant even help me once but they are quick to debit my account.