Contract Upgrade Denied after 6 Years of being a loyal customer !!!

Really disappointed with MTN. I have been a loyal contract customer for +/- 6 years and have upgraded my contract with no issues before. I am now being told i cannot be upgraded due to me being on review even though I have upgraded my contracts twice before with no issues. Apparently their systems have changed and there is nothing that can be done. This is truly ridiculous considering that for 6 years I never defaulted on my payments to MTN and remained loyal as a Contract and Prepaid customer. So disappointed with service and the treatment from MTN.