INCOMPETENCE OF MTN CONSULTANTS

Hi I am struggling to get help from MTN in general, I bought airtime and made a 2 minutes call. When I try to call again my airtime was depleted. When I call MTN prepaid I was told my number is on contract and when I call the contract side am told my number is on prepaid. What do I need to do to get this matter resolved.. It's infuriating to be taken from pillar to post with consultants telling me that they can't help. WHAT DO I NEED TO DO TO GET THIS MATTER RESOLVED.. IT'S BEEN 5 MONTHS TRYING TO GET HELP FROM MTN