iphone carrier not available

i paid for my phone in full at Verizon, and seitched just recently to T-Mobile. Everything worked fine for 4 months, but ever since going in deadzone areas in NC i came back unable to have a connection-i cannot make calls or texts and my iphone displays a no service bar at the top. i have restarted my phone several times and everything in settings and even did a hard reset; i cant connect to my carrier. i updated my carrier settings and everything involved. when i look in about it shows my carrier but says it is not available. when i click on it it shows this

it has worked fine for months and suddenly this is shown. i had cancelled my contract with verizon since January and just started using a cell phone service (T mobile) again in march. it's now June a few days away from july.