I’m not on the $5 plan but might as well be!
I’m sorry to hear of the experience. Have you raised a help ticket with Republic, so they might assist with what on the surface appears to be a coverage issue? If not, please consider doing so here: Republic Help.
Meanwhile more about coverage here: Republic Wireless Coverage. Also, some initial troubleshooting steps here: If Your Phone is Still Not Able to Make or Receive Calls on Cell.
I’m having this same problem today… I have no service literally anywhere period and I normally do with this phone and have for months… only over WiFi is it working and it started today with no warning or obvious reason…