Upgrade disappointment

I am so very disappointed in MTN. We wanted to upgrade our contracts early as we always do 4 or 3 months before our contract has to be renewed and now they telling us Oh sorry we have changed it to only be able to upgrade on the actual upgrade date. We were never informed about this personally and it is just ridiculous. I have a 3year contact and my phone is obviously not in a good condition anymore and to hear this when wanted to upgrade was just the worst thing ever. How can they just change the rules with a old contract that hasn't expired yet. Why didn't they just bring the rule in when upgrading to new contracts. This really isn't fair at all especially to those who have been loyal to them for years and years never missing a payment. Super disappointed that I now have to sit with a phone that isn't working properly for a few Extra months.