Dave is right, that is a relatively common microswitch. I know it is frustrating, but SOMEWHERE there is a bin of those in a warehouse of an electronics supplier.

I MIGHT suggest that you are wasting time and effort needlessly here:
You can just bypass the switch, cut the wires going to the switch, strip them, splice them together and you are done! BUT, the problem is, if you hit the top switch's 'down' end with the top clamped to the windshield frame, the pump will start and if you do not QUICKLY let go of the switch, damage to the linkage can be done quickly.

One way around this is to replace the bad switch with a small toggle switch that you can flip 'closed' when you want to put the top down! That way, when you put the top back up, you simply flip the switch to the "open" position and the system is protected from you accidentally hitting the 'down' button.

Or, keep searching for the exact part.............................................. ......................