I don't expect that kind of bone-job on this site. It does happen, but it also happens that we out that person, just as Jeff has done here. The six month lapse is not an issue. During that six months, Jeff sent the props off to be fixed, on his dime. He was willing to just pay the money, have them fixed and be done with it.
Now some of you say the manufacturer may be trying to bone this thing further. Come on, do you really believe that? Do you really think they are that hard up to try to sell new props rather than making money fixing the old props? Jeff could send them to another prop shop to validate the findings of the first, then then make trouble for that first shop.
Nope, the props were junk and the seller knew that. He had to.
Don't be blowing around your "buyer beware" crap. We shouldn't have to be on high alert on this site. We police it so we don't generally have to be worried.
If I were the seller, Jeff would have got his 500 bucks back. If for no other reason than to avoid this situation.