I informed PIP that my condition has worsened and they have stopped it.

Hello everyone. I'm Jon. 
I was originally awarded lower rate PIP for Cauda Equina. 
Post op has left me numb & weak below the waist with regular burning pains as a result of the nerves getting caught in the scar tissue. 
My condition has worsened with the addition of regular & severe cramps. 
I've tried all sorts including medications & exercises. Nothing alleviates it.
So I informed PIP of this & they sent me a form. 
I completed this with all of the original condition symptoms & the additional symptoms. 
They called for a telephone assessment where I reiterated everything I put in the form & they sent me a decision to say it's stopped with zero points on everything?
I've been through the mandatory reconsideration with the same outcome. Their assessment is totally contradictory to the information I provided. 
I've appealed to a tribunal now but I'm worried that I'll be stiched up so I'm wondering where I can source free representation for this?
Any information would be greatly appreciated. 
Thank you for your time and consideration.