[Q] Not getting 4G in my cell phone topic

I am not able to get 4g network in my cell phone.
I am using Lg g pro 2 smartphone. I bought it from india lg store, they had said that the phone works on 4g lte networks. I am using it in US.
I have taken att connection... att ppl is saying that there is no issue with the carrier...its the issue with the phone...
I even tried hidden menu options like dialling 5457#*838# and 5457#*350# but its ending with message "connection problem or invalid mmi code".
If anyone could help me to get 4g on my phone it will be greatly appreciated.