Hi, my name is tobo87! Why do I have to fight for what I have always been entitled too?

I was on ESA for years due to brain damage and unfortunately I went to prison for 2 months last year in January so I was changed over to this universal **** system finally after 2 cancelled appointments by them I had my call over the fone today the guy was really not helpful towards my illness and made me feel really uncomfortable, does anybody have any idea what the next steps are I.e timescale etc as I can see me already needing to appeal does why do I have to fight for what I have always been entitled too?
I have also handed in fit notes since April 22 without a gap