From twitter and facebook: "Due to some issues affecting recent purchases, we are turning off the ability to purchase a Lifetime Subscription on Xbox One and Playstation 4, until a fix can be determined. We'll have these features back as soon as possible." So, it is a know problem, but you probably should submit a help…
Are you sure it's not working? On the Xbox, the rifle doesn't have the firing animation, so it doesn't look like it's working, but it is putting out damage.
There is no "available" tab. That is a PC thing. It should be exactly where you described in your OP. The patch referred to is a PC patch released a couple weeks ago. The consoles don't get regular patches. Our last update was the winter event. There is a chance this issue will be resolved when the binary star update drops…