Non-AT&T LG G4

So I switched recently from T-Mobile to AT&T and kept my T-Mobile LG G4 using it as an unlocked device. Well during the switch the sales rep added what I'm sure he assumes are the correct APN Settings. After he set up the APN, I get a 4g singal but my phone is not receiving data rendering all my data reliant apps useless, which is a major inconvience. Any have any ideas on how to fix this get an lte or data connection running on the phone.

Thanks in Advanced!
Zpryce