Does my ATT iphone5 have issues with Tmo Prepaid?

[Mr.Womanizer]

i bought my iphone 5 on launch week last year, had it contract with att, earlier this year i ditched them and third-party unlocked it, and went on tmobile $70 prepaid plan. I notice it since i switched to Tmobile that it jumps from LTE to 4G to E sometimes even if i'm not moving. Is it something with the bands the phone supports? or is this a common thing with unlocked phones on different carriers? my phone is model #MD638LL/A black and slate. Can this be fixable or exchangeable by apple or someone?

 

[Applejuiced]

Sounds like bad service in your area.
Worth a try if you want to test out a replacement from Apple.