2 years, god lord! What is this guying doing to your car? I hope you have all this documented, ie work to be performed, a due date, parts, labor etc...
Why is it you can not go down and visit the repair shop, if I may ask? If this is a reputable repair place I would contact them (registered letter, in person, phone call) and demand your car back either finished or given proof that your original 6k has been spent so far on what?! Contact the BBB (Better Business Bureau), get an attorney, contact your Attorney General's Office, or threaten to sue (assuming you have grounds).
If none of the above applies you might be SOL or you will need to come up with a creative way to persuade them to help you out.