The iphone 4 is not an LTE or even a 4G capable phone on any network. Not even faux 4G( HSPA+). It is a 3G phone for AT&T's network. That is the hardware of that model iphone, not an opinion. So Edge is the fastest network it could get on t-mobile. I believe the rep was correct and was telling you that on t-mobile it would run on Edge. Which is really really slow. Why would the rep of a company trying to get people to bring phones in to his company to adopt their service lie to you or discourage you from doing that. I believe the rep was being frank with you so that you would not be disappointed with the service.