Still can't purchase Musescore Pro, even with Paypal

So I revisited my urge to purchase Musescore Pro, and I now saw that you guys accept Paypal. I have a Paypal and I have a Visa Gift Card with $50 in my Paypal. But for some reason when I try to purchase using Paypal, it says I need to still put in a debit or credit card with my Paypal to finish my transaction. Why is that when I already have a card in my account? I tried putting in the information from the Visa card that's already in my Paypal but it won't continue the transaction. Help!