Poor service

I took my car in because of an over heating problem. After a total of 3weeks nothing has been done. There were no flashing lights on my dashboard when I took my car in, when I fetched it today there were 2 flashing warning lights and the car had zero power. The workshop foreman indicated to me that a speed sensor had to be replaced. I agreed to this. When I fetched my car today,I was told by the service manager that it had not been done. I was not charged at all and told that the turbo is faulty. This was replaced a just over a month ago. On inspection of my car I found the engine speed sensor lying on the dashboard. What does Lindsay Saker Kempton think. They broke my car and are trying to shift the blame. This is outrageous.