Page URLs with extension

I did a search on this topic and found nothing that fits my exact question, so forgive me if it’s out there and I missed it somehow.

I am using a couple of plugins to make my site a multi-level marketing site. Everything works fine, so I’m good there. The problem I am having is this:
When a new user registers on my site, they are given a referral link. That referral link looks like this mysite.com/234 with the 234 being their referral number. If the user gets someone to register by clicking on their referral link, a new link is generated for the new user with the next available number being their referral link. It works perfectly, as I have tested it a number of times.
Another plugin that I am using allows me to create squeeze pages, or opt-in pages. I was told by the creator of the plugin that generates the referral links that I can make any page into a referral link by doing this mysite.com/page.php?ref=234
This is where the problem comes in…how do I get the original page URL that has the extension? I created an opt-in page called squeeze-1. If I try to structure the link like this mysite.com/squeeze-1.php?ref=234 it gives me a 404 error. The page is not found. My guess is that there is more to the hierarchy than just putting the php extension on there. WordPress automatically takes off the extension, and just ends the URL with the post name, or page name.
What am I missing?