To address OP's issue:
1. UA's P fare is indeed a F fare. The problem is it is considered as a Upgrade fare, which the pax will still get all the perks with F if nothing happens. But if there is IRROPS, UA will place the pax back to Y and waitlisted for F.
2. In term of the ticket problem with PL, check your booking with UA first. If UA is showing the exactly the same as what you received from PL, then there is nothing you can do until you travel. But if they don't match, I would suggest that you contact your state AG, as it is a better approach to get PL to listen to you despite numerous calls.