If you have an AP purchased/linked you shouldn’t need to call.
When searching for a resort, scroll all the way to the right on the screen below.
Of course, an offer needs to be available/offered for your resort and dates in question - which may not always be the case.
Make sure you are actually logged in when searching.
My last tip, I have a lot of problems getting the AP offer to show up sometimes. I have to use Chrome via an Incognito tab (called private browsing in other browsers) for the website to work properly.