Not fixing our bike

Good day<br> <br> We gave in our xj750 yamaha motorbike for repair and service at Henco Custom bikes in Hercules pretoria. This person advertise that he does custom bikes, and said that he CAN do anything on a bike or rebuild/customize it if nessesary. The major problem on my bike were a cdI. After 3 months this person is still making excuses anout fixing my bike, saying it were modified so he struggels.... and more and more excuses. The quote of R4130 included a new regulator, new cdi unit as well as filters and wiring of the bike. I already payed R3700 and NOTHING accept insolation tape on the old wiring were done. After much enquiries and fighting he now informed me I can come and take my bike with 2 loose cdi units but he refuse to pay any of my money back. Whay am I to do, I would like to take the matter on in the right matter rather than forcing my way into his work shop and being forced to violence. Please help me? He did borough me a scooter to drive to work with, but it is not even on the road, so at this stage I have a major transport problem.