How Can I Figure Out Who Is Calling My Phone From Restricted

If a number is showing restricted, unknown, or blocked then no one will be able to tell you the number, because there will not be any record of a number.

In any records that may exist it will only show that you received a call from a "blocked or restricted" number.  

Some phone companies, and even some specific phone models, offer a service where you can block private, or blocked callers, so I would contact your provider again and see if this is an option.

Good luck!