MTN customer care does not care

Hi have been calling MTN customer care to help me and nobody wants to help me, I am applying for a BOND, the bank needs a closer letter from MTN that shows that my account is fully paid up, MTN keep sending me statements and the bank comes back and insist on a closure letter, been explaining this and MTN agents keep telling me they do not offer closer letter. GUYS I am applying for a bond this is serious. I need a closer letter.