No Service

Tried all the recommended options to resolve the "no service/searching" problem in my iphone 7. Tested with the following but failed to resolve:

1. hard reset
2. reset network settings
3. updated ios (to 13.3)
4. updated carrier settings
5. changed SIM card (got a brand new SIM from carrier store) - the new SIM card does works flawlessly on my other android phone by the way

Am clueless now. Alas my pristine condition scratch-less, drop-less iPhone 7 is not having any service.

WIFI is working and everything else, except cannot make or receive calls. Please help. Thanks.