No Service, how to contact carrier

Wouldn't you need to contact whomever you pay for cellular service? I'm sure I'm missing something, what is it? I found this list of carriers, worldwide, for LTE coverage for the last few models of iPhones. But it does not cover, at least expressly, iPhone 8 Plus, and what's more, it shows just how many carrier options there are in many countries. Seems like you wouldn't need to see the name of the carrier on the device in order to know whom to contact -- just check your invoices for cellular service and call support for the carrier that provides it.

You could also follow these steps outlined by Apple for when you see no service on your iPhone.

You could also make sure that Cellular service on your device is active by going to: Settings > Cellular and see whether more information is provided there. For example, mine shows the carrier's name and, by tapping "carrier services" ways to contact it through the phone. Other information that may shed light on your issue may also be there.

Good luck!

-- JDee