Serious Issues with iPhone 7 Plus

iPhone 7Plus, iOS: 11.2.6.

1: Cannot make or receive phone calls including FaceTime.

2: Cannot word search in Messages.

3: Email refresh is delayed.

Reset phone multiple times. Reset network settings multiple times. Removed SIM card and set it back.

Problem started almost 1 1/2 month ago.

All of a sudden, phone calls wont' go out of received. The only option i have is to restart the phone.

Is it the phone problem or verizon problem? Anyone is facing the same issues?