Problem purchasing license

I found a couple of discount codes (20% off) for Scrivener so I decided to go ahead and purchase a regular Windows license. Since the upgrade to Scrivener 3.0 for Windows will be free for new purchases, I figured now is a good time to buy.
Anyway, I clicked the Purchase Scrivener link from within Scrivener just to make sure I was going to the authentic site.
I selected the regular Windows license ($45), and entered the discount code. It gave me a $9.00 discount.
I decided to pay with PayPal.
I was taken to the PayPal website where I logged in and saw that everything was in order. But when I clicked the Continue button in PayPal to complete the transaction, all I got was a blank page with the title “Custom Page”.
My browser is Firefox Quantum 59.0.1 x64. I had an ad-blocker turned on, so I disabled it and refreshed the blank page, but nothing changed.

I have been checking my PayPal account and e-mail and so far (about 1/2 hour later) there is no indication that a transaction was processed. I don’t want to attempt another purchase until I know for sure the original one is dead.

I sent an e-mail to the contact us link on the Scrivener store’s website but they’re saying it will be at least 2 days before they will get back to me.

There is no rush, as I still have a couple of weeks left on my Scrivener trial, but I don’t want to miss out on getting that 20% discount.

Any suggestions?