The screws on the bottom are standard Phillips parts (meaning not Posidrive or other crosshead format). Get a proper screwdriver from a tools store and if they are not in too bad a shape you should be able to undo them. I use Xcelite XST-101 Phillips-1. Alternatively, if they are pretty far gone, an Impact Driver might be worth trying.
Once you get it undone, try cleaning the switch, but if you are unsuccesful, contact support@eventide.com when they are having a good day and they may be sympathetic.
