Sorry to say it mate, but you are being conned good style, go and knock on his door and demand your money back, he has sold you a dog under false pretences, telling you it is part trained, as for the ear problem, thats a load of bollocks mate, and not your problem, he has sold you a gun shy dog simple as
I have had gun dogs most of my life, bought part trained and full trained dogs, but allways saw them work in the field, before handing my hard earned cash over, only ever had dealings once, with a gun shy dog, we tried everything in the book to cure it, but at the end of the day we couldnt