via the "special offers" link on the Disney website, I can book 5/8 -5/15 at the POP and get the public discount of 20% off. When I called to use my code (35% off) I was told no discounted rooms at POP available for those dates.
My guess is Pop Century is only available for the general public discount and no rooms are available there for the your dates with the pin code WDW sent to you.
Check your email and see what dates it is for. The public discount code is good for the dates I wanted (May 1st - 4th), but the pin I got that was a better deal for me, but didn't start til the 8th of May so I changed my dates to May 9th - 12th.
Our Authorized Disney Vacation Planners are here to provide personalized, expert advice, answer every question, and uncover the best discounts.
Let Dreams Unlimited Travel take care of all the details, so you can sit back, relax, and enjoy a stress-free vacation.