The reason is that, unfortunately, the [Availability/FS] (RIP 2010-2014) & [Availability/ETR] (RIP 2005-2014) Engines no longer exist.
KVS Tool Members can continue to access Regular Flight Availability via the KVS Tool Mobile Companion.
Is there a way to get a refund? If I wanted to use a website, I'd use EF. I specifically subscribe to KVS based solely on it NOT being a website. But availability is 90% of my daily use, so it's now completely useless to me.