Hi,
Sorry to hear you are having issues with FaceTime on your iPhone.
Are you still able to send and receive iMessages? Are you receiving an error message when trying to use or make a FaceTime call?
Confirm your Settings are configured correctly on your device to access and use all features for FaceTime and iMessage:
Settings > General > Date & Time > make sure your correct time zone is listed.
Settings > Phone > My number should have your phone number listed. If it is blank, add your number.
Settings > Name > Name, Phone Numbers, and Email > Reachable At. Make sure your phone number is listed and says ‘iMessage and FaceTime number’. If it doesn’t, you need to enable FaceTime and iMessage within Settings > Messages and Settings > FaceTime.
Make sure Settings > Messages > Send & Receive has your phone number and Apple ID email checked in the first box. In the second box, titled ‘Start new conversations from’, make sure both your Apple ID email and phone number is listed, but only your phone number is checked. If you do not see your Apple ID, click ‘Use Apple ID for iMessage’ and sign in.
Then, go to Settings > FaceTime > ‘You can be reached by FaceTime at’ should have your phone number and Apple ID email checked. > ‘Caller ID’ should have your Apple ID email listed, and only your phone number should be checked.
If you do not see your Apple ID listed, click ‘Use/Sign in with Apple ID for FaceTime.’
Lastly, if all of the above is configured correctly, and you are still unable to use FaceTime, reset your network settings and try again.
This should resolve your issue.
Hope this helps.