No dial tone on home phone

Home phone does not have dial tone. This has been going on for two weeks. I have spoken to several Xfinity Tech Support who did typical things like restarting modem. Most of the time they try a couple things and then say they are going to transfer me and then I am disconnected. Also tried online chat. After 10 minutes he came back on and said "it should be working now".  It wasn't.

I need someone who knows how to fix this to help. Can I get that here? I am at wits end.