I have faced an Available Now issue 3 times in two months.
When I turn it off from mobile web site, time to time it does not turn off.
Last month I have punished as I did not respond on time twice. However, I always response on time. If I turn it off on mobile web site, sometimes it does not turn off even it seems off. And today it says I did not response on time even I turned off it on mobile website.
Be aver that issue and always use desktop website to use this feature.