MPB Switched my Camera for Another's Brooklyn NY

MPB advertises that they pay good money for used cameras.  I had a Sony Cyber-shot DSC-RX0 II in excellent condition that I wanted to sell.  I arranged to send it to MPB in FEB 2020.

Initially, MPB acknowledged that it was in excellent condition and offered me $300.  I notified them that their offer was acceptable.  A few days later MPB sent me a "corrected" offer (which they admitted was unusual) and claimed that, during a 2nd inspection, they noticed advanced wear.  Their revised offer was only $100.  I declined and directed them to return my camera to me.

One week later, I received a camera from MPB that was NOT mine!  It was the same model but where mine was Made in Japan, the one that I received was Made in China.  It was also in poor condition.

I have repeatedly emailed MPB to ask for a resolution.  As of May 25, 2020, MPB has failed to resolve this problem.