This plumber overcharged by extending the amount of time taken to do the job. After diagnosing where the blockage was in the pipe, instead of snaking to remove the blockage he instead proceeded to unnecessarily go on top of the roof, and then under the house, all of which were a waste of time and of course added expense. He of course eventually came back to the original source of the blockage, however I vowed never to use this company again.