You have argued your point well, but are pointing fingers in the wrong direction. 99% of the problems you detail are due to dishonest, or incompetant, dealers - entering social #'s wrong, promising credits that aren't available, waiving activation fees, etc etc.
As for the billing issue, whether or not the customer receives a bill for two months on the first bill or just a prorated amount and then the full bill they are still responsible for billing from the day of activation. It is a shock to customers I agree but Nextel is not billing for service not used.
As for me, I am a Nextel dealer and have been very happy selling Nextel services for three years now. I am honest with my customers and don't have the problems you speak of.