Best Location Change in Seattle WA

I called for a plumber to come out and give me a diagnostics on my faul smelling house, that I suspected was a sewage backup in the pipes. When I called for an appointment I was told that it would cost nothing for an estimate. The technician was late, and wasn't even a plumber?! The technician that was sent to me said he only specializes in drainage?! He didn't work on anything, but I was still required to buy some fluid that was $65.13. I was told that he had to charge me something for coming out. Will never call this company again!!! This company sucks!!!