Hello, if you didn't get the email from eBay with the codes inside, then you aren't supposed to use them. However, it has worked for many people who didn't get the email, so who knows? I am just saying that if you didn't get the email and the codes worked for you, then be grateful! I highly doubt PayPal will make an adjustment for you if you were not in the group that received the original email. I got the email, and the code has worked perfectly for me.
And in response to someone's post, no, the seller does not eat the PayPal coupon. PayPal pays the amount of the coupon so the seller is paid in full.
...I also think the coupons might have been sent to buyers who spent x dollar amount (I know I have spent a LOT, way more than usual these past few months........ and I don't think I had gotten them previously)