Are both the name AND number not showing at all? Do any callers show on call display including from landlines? Do you subscribe to caller ID?
If the number is showing, and the caller is on a cell phone, in Alberta usually no name will show.
If it's only impacting your contacts it is likely an issue on your phone, or less likely but possibly on the callers end.
Have you contacted tech support yet? (Telus or phone manufacturer)
Which calling app?
When did it start?