In the majority of the service industry - if a service is not what you asked and paid for - you should be able to get a replacement or refund.
I had my car repaired by a garage to stop a knocking noise. I trusted the diagnosis, paid for the works - but still have noises. He looked at the car again, and priced me for a further job. How is it that a garage can carry out a service which did not do what you asked, and then charge you for a further service!?
Is this 'just the way it works' or should I be able to request that he fixes the problem, at no cost to myself. I speak from inexperience, but also from being quite peeved at paying for something that didn't need doing or what I asked for.