Some cards are accepted, and some aren't. PayPal sometimes accepts cards that aren't accepted elsewhere online, so you might want to hook up that card with PayPal and try buying credits that way. That's exactly what happened to me. I have a MasterCard credit card and when I tried to buy credits with it here, the card was rejected. PayPal accepted the same card, though, and I could buy WGT credits from that same card, as long as PayPal acted as intermediary.
PS: There are even some "full sets" that don't include any wedges. 