I will offer that the reason the carrier changed defense attorneys it that it disagreed with the recomendations of the prior attorney. It is not illegal, but the carrier has to weigh whether continued litigation is worth the proposed settlement. You should speak with your attorney.

Lastly, I do not see how you are suffering from the failure of a settlement unless you are no longer receiving permanent disability advances because the carrier now believes the impairment is less, unless you can no longer make a big down payment for a new car.

I would need more information to determine if the agreement was binding. Most carriers will not deduce any offers made unless they got significant new information or their initial attorney made a mistake of law or facts. If the attorney appeared to be authorized to make a binding offer on behalf of the WC carrier, then the carrier can not back out. If the offer was put on the record at a WC appearance before one of the WCAB judges and there was no statement by the defense attorney that he had to obtain authority for the offer [some public entities require the governing board to approve all settlements], it should be binding and the Judge will be upset with both defense counsels. Why does your attorney say it is not binding? I have to assume that your attorney is competent and knows all the relevant facts so should be correct in stating it is not binding [you would not be asking the question if your attorney said it is binding].