Rapid-Rooter

After draining tank, I asked the plumber to try to clear the bathtub drain and diagnose  the bathroom sink which was flooding from behind the wall..  He spent over an hour trying to clear the drain, both in the house and on the roof, with no success, suggested that it must be a broken pipe.   Said we needed a special camera to send into the pipes to find where it was broken, an additional $250 charge.
The man with the camera was unable to find the break, because (he said) the pipe was broken in such a way that it was preventing the camera getting all the way down.  Diagnosed that we needed workers  to tunnel  under the house and fix broken pipes, for which they were going to charge us $6700.  
Next day, I had another plumber come by. He cleared the tub drain in about 1/2 hour.  Also found that the flood from the sink was due to a broken pipe behind the wall.  Total cost to repair . .  $600
The plumbers were prompt , and  always friendly and professional in their demeanor.  I believe they made an honest mistake. But there's also no excuse for such a significant and potentially costly mistake. To their credit, however, they did refund the portion of the payment related to the attempt to clear the drain.