Disability premium?

Hello, I have received income based ESA for 5 plus years, standard care PIP and no mobility for 2 years for multiple mental health and physical disabilities.

I was told by courts at tribuanl to come back with my physical evidence after 2 years and now i have it, i have recently been back to another face to face assesment for PIP only to be knocked back when my conditions have worsened and currently waiting for a second tribunal.

My question is, should I have been receiving the premium over tge last 2 years? As I have no carer or partner. I was only informed last week by a DWP representative of this premium. Why would they leave it that long to tell me that? Any feedback is welcome. Thanks.