How can metro pcs do this?

when I got my phone it was advertised as 3G but when i talk to a technical support representative (cool guy) I was told since metropcs is coming out with 4g there now making 3g obsolete therefore that would be false advertisement, correct? I can't even watch a youtube video on my phone, which can be done on my friends older phones that arent even smartphones without a hitch. I just don't see how they're about to advertise phone is 3g and then not even give you a 3g phone. C.A. Lawsuit!