They actually said to you they were "Never going to reinstate you" In those exact words?
I'm deeply sorry for what you are going through. Jehovah's witnesses is the absolute worst religion for those who are suffering with any mental illness. They have zero compassion, zero understanding and make zero allowances - despite their well researched, shiny, polished publications replete with all the latest buzz words. They drive a horrific number of people to suicide every year. I'm so sorry, no one deserves this.
I do have to say I've never heard of someone being told they'll never be reinstated (even though they may be thinking it). But knowing watchtower as I do, if your mental illness is very apparent to the public...as cruel as these words are ...you are of no "use" to them. As a recruiter or worker.
Watchtower is a cult. A machine that uses members for profit, whether it's 'managers' know it or not it's nevertheless a fact.