Lack of Straight Talk 3G/Data

[DethDonald]

I'm re-posting this from a post I made in the Android Question section.

Hi, I'm having a problem with my straight talk phone. I opted to bring my own phone and am having problems with 3G/4G and sending text messages with images or other media on the T-mobile SIM card, I do have a 4G LTE SIM card. I can only send images over MMS when I am on a T-Mobile connection but not while roaming. I also am unable to ever connect to a 3G signal (4G is not available where I live). I know that a 3G signal is available in my area as my sister uses it while at my home. I have set up my APN just as the website stated and am at a lose as to what to do.

I'm using a Moto G. I didn't bring it from a different network I got it unlocked.