Bad customer service

I have been calling MTN legal department to obtain my paid up letter that MTN says I owe them for a contract I had with them 2 years ago, funny because they agreed to move my number to prepaid at the end of my contract and I don't understand how was it done if I owed them.

now that I have paid them to get them off my ITC profile, their service is nonsense. I called this morning and they put me through to 5 different consultants who are claiming they can't assist me because my account is in the old system and they use a new system. Like what nonsense is that? when the 5th consultant puts me through I have been holding for the past 2 hours with no consultant picking my call. Even emails are not being responded to. So maybe MTN must tell us if customers need to go straight to the head office to get a simple service!

I am extremely frustrated because I need this letter urgently to submit for my ITC clearance.