Wrong diagnosis!

I am extremely disappointed with diagnosis your agents had provided me last week. I brought my vehicle in to have it checked becuase of a noise i thought related to the valves.It was diagnosis was that the timing chain had to be replaced. After replacing the timing chain (and thousands of rand later) i was suprised that it was not the timing chain at all and the same noise is still there. What kind a *******, who takes responsibility for not having the car inspected properly and what gets done about something like this?