Your comic book seller says he accepts VISA/MasterCard, in addition to PayPal.
Did you actually continue through eBay's checkout system and submit your credit card payment online? Sellers are allowed to have valid online CC Merchant Accounts, in addition to PayPal.
However, if the seller is asking you to telephone or email your CC# to him, he's in violation of eBay policies.
If you haven't privately contacted him with the info, then your payment is still outstanding. You should be able to access any of eBay's Pay Now links and select PayPal.
Graciously Grin When You Growl