If the control won't rotate, the immediate thing to do is to figure out what's keeping it from rotating. Did you remove it recently by chance? There are two pieces of hardware in the switch that allow you to set the number of positions active on the switch, and this is called out in the directions. It's completely possible to accidentally set the switch up to be one position, then it wouldn't move at all. If the switch is loosened and/or removed for whatever reason, these bits of hardware can move and cause the same problem.
It's also possible that debris has lodged itself in the switch and caused it not to move.
We have the switches custom made for us, so you'd have to order a replacement from us if that ends up being necessary, which seems very unlikely.