First PIP claim

Hello all,
I put in a claim for PIP for the first time, was meant to have a phone assessment on 16th April which was cancelled that morning, i have it rebooked now for 8th May. To say i am dreading it would be an understatement and the fact that the government are changing things, i've been told i will fail and have to do mandatory reconsideration which is too be expected but i have been told most people are having to go to tribunal.
I am already claiming ESA in the work group, i go to the job centre to see adviser and she thinks i should be in the support group and should have been claiming PIP a long time ago, i'm due for re assessment for ESA again this July so i'm dreading that as well as last time i had to go to tribunal for that as well which did go my way.
I'm basically asking for any help and/or advice, i needed help filling in the PIP form as i can't hold a pen.
I really am dreading this, thank you.