"H" but never 3G
The only problem is that it isn't true 4g, just a more developed version of 3g.
Bascially H = 3G in you're area thats why you don't see 3G. Go into an area that doesn't have "4G" and you will see 3G if its available.
T-Mo's definition does not meet the International Telecommunication Union definition of 4G. Mad Hatter logic here - a word means what I want to to mean!