My IPhone 6 Cell # Don’t Show up in Settings- Under Carrier it Say “ Not available “- Also there’s NO Carrier Info on my Main Page, just 4 Bars & LTE ONLY

I’ve took it to my Carrier & contacted Apple about this issue, I’ve Reset & Reset & Factory Reset & Factory Reset, Changed Sim Card, Hooked to Diagnostic at Local Telephone Co. & Showed Phone has NO ISSUES, like I said I’ve been Running From Place To Place for a YEAR NOW, I’m a 51yr. Old DISABLED Linemen With a Broken Neck & Just CAN’T Keep RUNNING From Place to Place & Try’n “ USUALLY “ The SAME STEPS that I JUST DONE EARLIER... And By The Way These Steps are taken several hours to do, and I have to keep ReInstalling my APPS EACH TIME.... SOMEBODY PLEASE HELP ME OUT....