It's important to keep your customer in the loop.
If you get hung up like this again, let the customer know as soon as possible that you are having a problem and how you are trying to solve it.
In this case, after 24 hours, clearing my cache and tossing my cookies, if it still wouldn't send the customer the right information, I would give him a Paypal invoice, noting the eBay transaction number and title in the inbox. And let him know separately that PP's Buyer Protection is at least as good as eBay's.
In some ways it is even stronger.
When he pays the PP invoice, print the shipping label and ship.
Mark eBay Paid manually.
Leave feedback, noting the date of shipment and service used.
Don't sit in a box, waiting for eBay.