Pinecone
En-Route
Fact is there is no such thing as a "pre-buy" inspection, it's a made up thing. There is no regulatory guidance or stated procedures as to what it is supposed to encompass and in most cases it's nothing more than a short conversation between the prospective buyer and whoever he choses to do the look-see. In the OP's scenario what should have been done is an annual (or in this case conditional) inspection with an agreement between the parties that if passed the sale is made. Even if it does not pass there is still a logbook entry with a signature, the inspection is complete and not due for another calendar year and a list of discrepancies exists which the two parties can negotiate over.
I know this doesn't help the OP but people need to get this whole pre-buy nonsense out of their heads or at least understand that this entire concept of buying a machine like this (sight unseen) is a crapshoot and be prepared for the possible consequences.
To the OP: sorry, I don't mean to be harsh on you personally. You should have been told this beforehand. My only advice now is follow Bell206's advice - get it out of that shop, lick your wounds and regroup.
Why should I have paid for an annual that benefits the seller if I don't buy?????????????
I agree that a pre-buy should cover much of the same things, but it should not be an annual. The annual includes things like lubrication of things and checking and adjusting things that don't need to be part of a pre-buy.
But even then, there can be issues. There is a report floating around here about a guy who had the shop do a pre-buy, based on doing the annual inspection inspections, such that if he purchased the plane, they would finish the annual doing the lubing and adjusting that is part of it. They did the "inspection", gave the plane a clean bill of health, he bought it, THEN they found major corrosion.