Hello stevewiebe,
Welcome to the Apple Support Communities!
I understand that you are no longer hearing any sound from the receiver on your iPhone and realize that you have gone through some great troubleshooting steps already. To continue this troubleshooting process and to ensure that all valid troubleshooting steps have been completed, I would suggest reading over and working through the suggested steps in the attached article below.
If you can't hear a person on a call or voicemail or if the sound quality is poor on iPhone - Apple Support
If, after completing the steps, the issue continues, it may be necessary to contact Apple Support using the link towards the bottom of the article.
Have a great day