I have to ask, within the 24 hours of him sending you his carb and you stating you would send yours the same time when you got his tracking number. Ummm what happen that you still had the carb. It should have been shipped right. That would mean if you had planned to ship you carb it would have been off the car, boxed and ready to go.
Then you have time to buy two new fittings all in 24 hours... WOW. how about this, you got his carb and wanted to try it and if it was better then yours it was a deal if not then back it went, well maybe it would go back.
It appears to me this guy allowed you to borrow his carb and not by his choice.
Care to share the persons name how bought the car?
Any proof that trade took place.
I just don't like people seem to leave parts of the story out