ringer problems on phone
Iphone 7 does not ring for incoming calls
Some things to check:
The ring/silent switch on the left side of the phone: How to put your iPhone on vibrate, ring, or silent mode - Apple Support
Settings > Phone > Silence Unknown Callers: Detect and block spam phone calls - Apple Support
Do Not Disturb: Use Do Not Disturb on your iPhone, iPad, and iPod touch - Apple Support