Item paid for using credit card (have a PP acc, but the txn doesn't show). How to open a case?

[moozie05]

I paid for an item using a credit card (I also have a PayPal account). When I tried to open a resolution case, I cannot proceed without a PP transaction number. I have not received the item (it has been over a month), and the seller does not respond to my messages. How do I open a resolution case ?