There are three levels of buyer protection available.
The first is from eBay and is in the Resolution Centre at the bottom of this page.
You have 30 days after the last estimated delivery date to open an Dispute.
Always use that system first.
For that you need the transaction number in the email you got from eBay.
The second is through Paypal, but many 'guest' buyers don't use Paypal. (Well, your credit card was processed through PP, but you probably didn't see thatl)
And the third is through the 1-800 number on the back of your credit card. Check your cc invoice for the payment then phone and ask about a chargeback.
If you need more help, c'mon back here.