Payment was made but item does not appear in my purchases

I just made a small purchase with Paypal, starting at the 3DS Max Asset Library, as I have done several times in the past. It sent me to the CG Trader check out page where I chose to make the payment through Paypal. When I hit the "Pay now." button, it looked like I was being sent back to "CG Trader." Rather than arriving bact at CG Trader, I landed on a "404 error" page.

I immediatly received an email from Paypal stating that I had sent a payment to CG Trader, for the purchase. I never received anything from CG Trader. The purchase does not appear on my CG Trader profile/purchases page. The Autodesk Asset Library tells me that I need to purchase the item before I can download, even though I have already purchased it. I need help. Thanks.

Here is part of the email from Paypal:
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To
Russell Welch
Sep 29, 2018 11:50:47 PDT
Transaction ID:
76L91754R9691024E
Hello Russell Welch,
You sent a payment of $15.40 USD to CGTrader
(payments@cgtrader.com)
It may take a few moments for this transaction to appear in your account.
Merchant:
CGTrader
payments@cgtrader.com
Confirmed shipping address
Russell Welch
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