xoom ungrade to 4g

i got the xoom since came out vzw say will be upgrade to 4g 90 day still wating i belive that same way we get a contract with them on 2 years they need to keep they same with us i been lossing 4g here beacuse my xoom is not ungrade yea i send a letter to crs see what they can do if they can not keep the part of the deal i belive they need to give me a 4g table or money back and let me off contarct

can someone help