I tried yesterday and today to do the top-up thing... I'm going US visa to game currency, no paypal. I'm doing small amounts... $5-$10. Whenever I try, it accepts my credit card information in the slots, I click confirm, I get no confirmation from the website, and it loads a new blank credit card screen. I hope that makes sense.
I feel like if this feature is not working, there should be a note about it on the page until it's fixed.