Did you Reboot Phone? And click Reset Network Settings as well
And what phone do you have? PM uses Telus and Bell Network. Telus is in the process or realigning some 850 Mhz channel on its 3G network for other use. People who have phones that is not whitelist on PM VoLTE list (some older phones) and those do not have 1900Mhz (phones that are not designed primarily for North America) will have voice trouble.
Check if your phone has VoLTE or if it's VoLTE is compatible with PM network here
https://www.publicmobile.ca/en/get-help/articles/volte
So, depends on the phone you have, it might not be something that can be fixed unless you change phone, or if your phone has VoLTE, then you can move to Koodo or Telus
