MTN charges loyal customers upgrade penalties - Avoid them, Go with VODACOM

I upgraded my sim only contract with MTN after continuous calls from them requesting me to upgrade, 6 days later I went into the store and told them I would like to upgrade to a better package which includes a cell phone. They advised that normally because I am within the 7 days they would be able to cancel and upgrade at no cost but due to the system initiating the contract well before it was signed I have to pay an upgrade penalty. As a loyal MTN customer it is frustrating that I am charged a penalty for issues on their end. I regret signing this contract with them, should have gone with vodacom or cell c instead.