UKPassats

Ok 8 weeks ago my Passat estate broke down. The 3rd piston was broken and the engine siezed, I was recommended to an engine build company and they put a new top on the engine, water pump and timing belt, also a new clutch and fly wheel, I went to pick the car up and the engine management light was on, I enquired about this and was told it was glow plugs but it would be ok to drive, as I was driving home the car started juddering going up hills so I called the garage and retuned the car. Later in the day they call and say I need new injectors and a turbo, this was 3 weeks ago and the car is still sat outside the garage, what should be the next step I can take to get my car back, they have tried injectors but the still makes noises. I am pulling my hair out because It doesn't seem like they are rushed to get it done and I feel now I have paid for the first part of the engine build they don't want to carry on,