I hired a contractor to preform a restoration after a house fire. They had agreed on an amount of $517k with my insurance company. I signed a contract with them for $517k. I had previously had met with an architect, per him the stairs to the second floor needed to be extended because they were in violation of code, and to extend them we would have to move our master bath. To accommodate the master bath being moved we planned a small addition off the master bedroom over the living room. To offset square footage and cost we are not rebuilding a office on the second floor. I gave them 120k to start the job as per the contract pay schedule. Right after that they said there was issues with the permit and work would not be able to start till that came through. Now a few weeks later, they have sent me a addendum to the contract saying the total due is $732k and we need to pay them the difference out of pocket. Can I fire them at this point and get my money back?