Are you sure that it's locked to PM/Telus? If it is then call Telus however it may be locked by another carrier such as Bell or Rogers and in that case you have to just call one of them.
I'm unsure if @lomashu's iPhone device is already being used at Public Mobile, but if it is, it couldn't be locked to Bell or Rogers. Also, if it is locked to Telus, contacting Telus Mobility isn't necessary. As stated earlier in the thread, Pubilc Mobile can get it unlocked.
@lomashu Public mobile does not lock phones……….maybe if it’s a stolen pre used phone that they sold to someone.. haven’t heard of this ever happening .. sim lock is a different issue
The iPhone 7 is from a time that carriers did lock devices, and Telus/Koodo locked devices will appear to be locked to Public Mobile. Public Mobile will unlock these devices.