Be very careful - changing builders during construction can be very problematic, even more so if litigation is/will be a factor. Many builders will not take over another's partially finished job because of all of the issues involved so you could be left w/ a partially finished home and a longer time period paying interest on a construction loan.
If you are close to completion or just started, it might be better to either let them finish (and then have them pay to fix their mistakes) or start over from scratch.