Its a shame that the turbo has seized, but I have sold a lot of car parts in good faith to guys on this forum, if someone came back over a year later with a grievance about a mechanical part, I don't know how much responsibility I would want to take for it.

If you bought it at the wreckers they would most likely tell you to tell your story walking.

If the seller was still able to contact the guy who reconditioned it, he might offer to have a look at it for you free of charge, but you would be counting on the guys good nature as used high performance car parts dont have long warranties.