Broken drill bit in root c?

I just went to the dentist this morning for a root c. A piece of the drill bit broke off into the c. It is a pretty good size too. I am not being charged for the root c (today that is) but I was referred to a endodontist. This one is going to cost me $98 for consultation, $150 - $300 for the removal of the instrument piece, and $980 to finish the root c even though it was almost finished. I was driving an hour to get to this dentist because they were allowing me to make payments that suited me. My insurance recently expired and I am low on funds. The endodontist wants all the money in full tomorrow. I know that it is a good thing that the dentist is not charging me for the root c that was completed today, but should they not be held responsible for the other bills I am going to have due to their mistake? Any advice is appreciated.