I also had this problem, and I used the good one to copy and make a pair out of hard maple. Painted them black, been on there now for about 3 years, and you'd never know it unless you specifically looked closely at the feet. This is a very common problem with this unit.
You can order generic replacement feet from parts express.
I just went through the same thing looking for feet for a SA9500.
I found original replacements on the bay but wasn’t willing to pay $28 + shipping.
I found 4 great replacements for $6 bucks shipped. Not stock but the same hight & diameter close enough for me.