Iam truly gutted for you, iam fuming just reading the posts, I like a lot of people, recon the garage owner is hiding the truth about the damage from you, it's totally shocking behaviour from the owner to treat you in this way mate.
Seek legal advice and it's good you managed to walk away without resolving to violence !
Iam not sure what else to say mate other than I hope you get it sorted out, but even getting compensation won't help, due to the condition and work that's been put into the car sadly
Iain