To the OP, I had a skeletonised 6497-based luminor fall out of the waist pocket on a hoodie (put it there during a weights session to be safe, forgot it was there when I took it off , it landed on the flat side and made identically the same size dint in identically the same spot. It fell onto a tile floor, the crystal popped out and the movement dislodged, it looks identical to the pictures you listed. I can almost guarantee the same thing happened to the 26.
PP is a great system, but shows its inherent flaws when there is no information about the purchase, such as an eBay description. The only thing to do that would be 100% effective is to set up a forum-based escrow system, and that would be bad for so many reasons.
There is no easy solution, hopefully you can recoup your costs by selling off the bits as parts, and getting yourself a shiny new 26.
Good luck mate.