MTN- Customer Loyalty for what

My Current contract has been due for an upgrade for the last 3 Years and when I Finally decide to give in and upgrade due to the numerous call and messages, my consultant advises that my account is coming up with a credit vetting issue. This is despite being clear on all other entities that I contract with and having been with MTN for over 15 years and never defaulting once. My consultant cannot give me clarity on what the credit issue is and I have no access to contact that area directly. Surely this is not in line with the National Credit act where companies are required to give full disclosure should an issue like this arise. I have tried avenue and have been given the corporate salute.