Hey Hampton, VA.
Have you tried Camara City? He usually has a stock of used filters, prices and supplies are spotty but hey, instint gratification.
Another suggestion Ritz Camara. There supply of in store filters are also spotty but they were running a special buy two get one free, making them economical. Looks like you need a 77mm filter, don't know if they carry that size but worth a shot. I do know that they carry both the 85a and b though.
Good luck.
mikey d