jdsam

Hi there. Im new and hoping someone can help. I recently purchased a 52 plate Ford Galaxy.A brand new turbo was put on it before I was given it as it went on the test drive. At first it drove really well and then all of a sudden it started losing power and the turbo never kicked in. Took it back to the garage it was purchased from and they replaced the turbo again. It was like a brand new car when I got it back.The power and speed in it was excellent. I have had it back now just over 2 weeks and the turbo has stopped kicking in again. Also it was put on diagnostics test and showed no faults. Has anyone got any advice on what to do next. The garage is a nightmare to deal with and there is only a couple of weeks warranty left on it. Any help is much appreciated.