Carried Over Airtime exiped too quickly

On 12 October I upgraded my contract whilst having over R1000 of airtime still available. Upon upgrading, the balance was carried over, but expired on 26 October. Upon researching similar situations, I came to the realisation that the airtime is supposed to expire after 30 days, not 14 as was the case with me. In addition, the consultant at the branch did not inform me that the airtime will expire at all, and merely assured me that my airtime will carry over. While I find the expiry of this airtime totally unacceptable and the grounds for my decision to never again sign a cellphone contract, I find the situation whereby I was given only 14 days to spend over R1000 of acumulated airtime equally unacceptable. It is my belief that I should have been informed beforehand that my airtime will expire, and also that I should be given a proper amount of time to spend the accumulated balance - at the very least the 30 days promised by MTN.