spotlight is always on and switch is not working
If we eliminate "magic" as an option, the only thing that makes sense here is that you have not, in fact tracked all the wires properly (or at least they are not connected the way they should be.)

If you disconnect and insulate the wires connected to the switch (circuit breaker off, of course) does the light still come on? If so, then you don't have two defective switches (which is pretty unlikely anyway) – you have a wiring error.