How long will the servicing of my car take?

I took my car in for a service 08/10/15<br> I was not happy with the car as there was a shuddering sound when I started the car to which I sent Cindy Voges a video of what the car did and took the car back in. I was then told that they could not find the problem after waiting the whole morning at Ford for them to inform me what the issue was. Thereafter, she escalated the issue to head office technical. After following up several times after this, I had still not had any feedback and was worried that I might be making the problem worse by continuing to drive the vehicle (I am on the road a lot). A solution to this should have been suggesting that I bring the car in and they give me a courtesy car until they know what the problem is in order to avoid any further issues. My car is still under warranty and after being completely loyal and passing other customers (i.e. my family) on to this particular dealership, there should be some sort of customer care and relationship to keep customers happy. I collected the car last week and still it is not fixed - who do I escalate this problem to as I am becoming increasingly frustrated!<br>