AMS interview questions

AMS negotiated the salary before commencing the interview process. Once that was settled, it was three very quick interviews. Upon the completion of the third interview, the HR rep at AMS called me to finalize the offer and confirm the salary to which everyone had agreed (including everyone in management). She said she was seeking some final approval, but that everyone was excited. I received a call yesterday telling me that they had to renege on the salary amount upon which the had initially agreed. There was no other feedback other than that they were not able to maintain their commitment.