You need a lawyer,, but
they are selling 4G (large) phones,, with a lot/little PR about "their" 4g (small) networks..
I am sure that if you bring out the 10X eye loop, you will see that they do not guarantee the 4G network availability,
but when they have sole a bazillion 4G phones they will be able to afford to up-grade to a 4G network..