IPhone 6 No Service issue?

My iphone has stopped getting signal, although I can still search for and see carriers in Settings>Carrier, so I'm wondering if it may not actually be a hardware issue if it's still half working.
So far I've updated my iOS, reset network settings, replaced the sim, and done a factory reset. Nothing so far, any advice or ideas anyone might have would be greatly appreciated!

I had this happen on my iPhone 6 and eventually took it to the place of purchase, where they replaced something--damned if I can remember what--in about four minutes and did not charge me for it. I remember the guy saying it cost four or five dollars, but customer satisfaction was worth a lot more.

So consider taking it in.