EC25A roaming connection only not 4G lte

I have problems with my EC25A I only get roaming connection my SIM card is from simple mobile

I know EC25A has band 2 4 12 and simple mobile has all of them why I don’t get any 4G LTE connection or I have to have T-Mobile SIM card …

And there’s any possible I can lock some bands so I can get better connection with a different carrier company

No help why am I just getting roaming when my carrier band is 2 4 12 I can get 4g connection

You can refer to the following command to lock the band frequency.
at*cell at+qcfg=“band” at+cops

What does



You could lock the modem to LTE on a particular MCC and MNC combination using a form of the +COPS command.

Let’s say the MCC you want is 204, and the MNC is 20. The AT command for that is: