You had 30 days after June 17 (the last estimated date for delivery) to open the INR dispute.
While it is polite to give the seller a little leeway, the shipper (USPS?) cannot show any movement since June 9th.
Chicago has turned into a Black Hole for USPS and some members have reported shipments being moved hundreds if not thousands of miles before getting moving again. The usual WAG is that an entire container was driven to another terminal and the shipment was in that truckload and finally started moving again.
However.
If you feel polite, allow the seller until Friday (your choice) to show movement, then escalate to a claim.
Tell the seller that when the shipment arrives, he should send you a Paypal invoice and you can return the refund.
Because you are in a transaction with him, you can give him your email address for the PP account.
This is not the seller's fault, but it is his responsibility.