how to file a dispute?

[candparris_0]

I ordered an item on July 17. I have already paid for the item and received a confirmation email. The seller never marked the item as "paid". I have tried contacting the seller 3 times to get tracking information, to mark the item correctly, and to give me a refund, but he never responded. I have tried to file a dispute but it wont let me because it says I have not paid for the item. Im at a loss here, what can I do to resolve this issue and report this seller?