I curently have a Samsung Galaxy s Vibrant 3g. I am grandfathered into an unlimited Data plan. I was thinking of upgrading to the Samsung Galaxy s II 4g. T-Mobile says that I need a different Data plan to get this phone. Is this a ploy to get me to give up my old plan, which I've been paying the same price for, for a number of years? Or is there a need to have a different kind of data plan for 4g?