Determining the problem is more than half the work in electrical service.  I do not use the "replace each item until something works" method....  If I say that "its" the problem and "it" doesn't fix the problem, I work until the problem is fixed and "it" costs you what I originally quoted you.  I have tools and experience that will guide me to the correct solution and you will be provided an accurate estimate for any work needed to repair the issue.  Yes, you should get what you paid for.