I had no idea this thread existed before you sent me the link. also on the pretense of mail fraud wouldn't apply in this case. You held a private transaction for a used car part and the part was damaged by the United States Postal Service. You were not deprived of anything or schemed into buying a counterfeit item. On top of everything the actual value of the item is less then $70. furthermore you are in a completely different Court District then I and if you are thinking "Oh hey federal court" they don't take cases of this level.
You got the item you paid for. USPS damaged it.