Telkom doesn't let their customers upgrade earlier

I had an incident with my phone yesterday, and Telkom refuses to upgrade me earlier. I'm on my 19th month now, and would just like to know what telkom has to lose when upgrading me earlier?? It's me who's gonna have to sit with the phone for a longer time...Being without a phone is so frustrating, and I can simply not afford buying a new phone now to use for 4 MONTHS before upgrading anyway! A friend of mine upgraded with telkom earlier, after only 6 months, after having trouble with his phone... but me who paid for my phone for 19 months cannot??? If I buy a phone now I will not think twice as to cancel my contract with Telkom when August is here, this is simply unacceptable.