Upgrade failure - Dishonest

Previously with Nashua, thus accounts were set up by them, MTN is refusing to upgrade our handsets because of some Internal error (they say) on our account, the way it is set up. MTN is just being dishonest by refusing us an upgrade that is due. now it is left to us to fix their internal issues on our account ???, tried Nashua, and even them said that MTN has to fix it as it is an internal error on our account. Every excuse in the book is used to deny the upgrade and MTN is refusing to assist internally to have the problem fixed ? dial 808 and have them fix it , really - nobody EVER answers that number, and why must the customer for many years Fix an Internal issue ? when all nashua accounts was handed over to MTN, surely someone was tasked to ensure that every account is set up correctly, or in a manner that would integrate perfectly to MTn's systems, ( guess that is too much to expect from a company that cant even answer their own phones ), I have never experienced such pathetic service levels, and the unwillingness/incompetency of MTN staff to assist their own customers !