Have you contacted AndyMark to let them know about the failure yet? They might be able to improve future versions of this product so this does not happen again. That being said, I think a small screw lasting 2 seasons like that is pretty impressive.
You could always try something new like the
Linear Servo, although it appears that is optimized for the Sonic Shifter.
I do admit that it sucks when something like that fails this late in the build season, at least it wasn't in the middle of a match!