Steeling data MTN

While Im sleeping Goodday. I have such a problem wih MTN I bought airtime 3 times in this week and every night put off my phone. When I put it on the next morning my data just vanished. I asked my daughter to help me, but the help centre didnt even care to.listen and help. I dont know what to do anymore. If it goes on like that Ill just finish up my contract and run. Ive been at Cradle stone mall and they couldnt help me either......