New ceiling quote?

Hi, I have had a very very large quote from a builder in relation to replacing a ceiling. The ceiling had an impact that has caused the plaster to crack and come away. The timber underneath evidences a leak at some point that has been fixed. I want all of the old timber removing and plasterboard adding to the joists. It’s for my living room and it’s a really small room but the quote has three zeros next to it. I don’t know if I need to contact someone from a different trade instead of a builder to do this ? Also sounds incredibly high price for a small job. Can anyone advise if I am being ripped off