A builder is trying to excessively charge me for a project that they were not satisfied with

I was hired to do some concrete work and the owner wasn't satisfied with it and then the builder came at me and said that there was an issue with concrete work, so we came to an agreement that I was going to pay for the demo to take it down I was going to pay for the demo at my cost and once the demo was completed they gave me the invoice and it was 5 times the expected amount (bid that the builder went out and got). They are now trying to charge me for work and materials and time that was never mutually agreed upon. I had completed the first and second levels and was informed that they were unhappy with the first level. I told them I wasn't going to do the 3rd level because it was too high and wasn't safe, and if they were already unhappy and wanting it demo'd then why continue. Then the builder and I agreed that we were going to take one portion of the concrete down, so there was no reason for them to have the scaffolding and now they want to charge me or the scaffolding and 2 other charges plus other excessive charges such as picking up materials, scaffolding, meetings, "problem solving," checking and looking over work, communicating in via email/phone, going over questions, moving boxes, etc. I have insurance but need advice on what type of lawyer to consult with regarding this. Thank you!