I've had troubles with ebay and parts before. Bought a tailgate that looked nothing like the picture. I specifically asked if there were any dents or rust. Seller said no. I got it and it was a rusted bent POS. I did end up getting 1/2 refund. I still ate about $60. UPS lost 1/2 of a package I got from a board member. They lost all the bushings, bolts and brackets for an ECE sway bar kit. Box clearly marked 29lbs and just the bar arrived which weighed 21lbs. Many useless phone calls later I ended up buying almost $80 in parts from ECE to replace what was lost. The seller was great and offered to pay for some. I only asked for $40 and he sent it right away.
As for your situation. You're screwed. Most places don't care about customer service anymore
Why? I have no idea. I think a lot of companies have that 30 or 60 day return policy to protect themselves from poor quality and fit parts. Think about it. How many guys buy a part and put it on the truck immediately? Not often. We buy parts as money allows and it's sometimes months or years before they are installed. The unfortunate reality is that a lot of parts don't fit correctly or are not even the right part at all. The company still made their money and you get to keep the part! There are some great vendors on the board with great customer service. I just wish there was one close enough to drive too
Shipping is killer.)