I took my 05 g35 to a local performance shop to to an engine swap. They told me it would take 2 months to complete. I got a invoice signed and dated by the owner . I paid 2 3rds of the money up front and still owe the remaining balance apon completion. Now its been 5 months and my car is completely disassembled and has no motor. Ive heard every excuse about why its not finished and im sick of it I want my car. What can I do?