Mike, I'm a buyer and seller on ebay, and I have had only a few situations where I bought something and it came like this and never saw this kind of response from the seller.
That seller is a complete jackleg and you can file a Significantly Not As Described case, request a return and he has to pay $130 to ship a broken computer back, which he will not do.
His responses are totally inappropriate and he would lose a case in a heart beat. UPS would deny his claim as well, they would take one look at the pictures and say incorrect box, incorrect corner reinforcements, incorrect space between contents and outside of box, and incorrect padding material. I bet that box isn't even rated for what they used, and USPS is not UPS. UPS is notorious for their trick guidelines. Pack it like they say, it will more than likely survive. Should have used a triple wall heavy duty box with expanding foam to ship that. Manuals should not have been in that box either.
You can still open a case and ebay will find in your favor based on his poor responses and the responsibility he has to get it to you right, not to the shipping company right.
Since the item is damaged, HE has to pay to ship it back, not you, and he isn't going to do that and risk losing the case. Its also in a compromised condition and contains implosion risk now, UPS will not ship it back either. Its important that you don't talk about taking it apart or wanting to keep it at this point. You'll end up keeping it and get your money back as you deserve. If you don't have the packing materials he cant get the claim from UPS, this is between HIM and the shipper not you.
Bottom line is, if I had done this to you, I would have issued a full refund, apologized and it would be booked as a loss, because I know its my fault, I don't want to pay that kind of money to get it back and then deal with it.
You also have charge back rights on your credit card. Many sellers gripe about the protections for buyers, this jerk is why they exist, and I support the rules here.
If any of you want help when you get screwed like this, PM me, 18 years of experience and never lost a case as a seller (2), and never lost a case as a buyer (3), because I know whats right and wrong and how the rules apply.