Fences has stopped working lately, thanks to a known bug. As suggested, I've tried to uninstall it and install again the previous version.
However, my key doesn't work anymore, and I'm 100% sure it's the right one.
Every support procedure leads me to canned answers which don't help at all. It seems that Steam purchases can't be activated more than once on a computer, which is another problem I'm not responsible for either.
What should I do?