No interest in giving feedback

I have written report after report begging for feedback from MTN, and they never resolve the problem , the problem is, I have overpaid my account and want a settlement letter and my money back but I get apologies instead of a settlement letter and my money. What will it take to get feedback or are they only concentrating on recruiting new customers and once you in this is how they resolve issues? I want to know why am I being treeated this way as I have overpaid what was due and I want my settlement letter.