PIP renewal, mobility.

Hi, I've received PIP renewal form in post, when I was on DLA, I received low rate mobility due to mental illnessess/overwhelming psychological distress. when it changed to PIP, I was not awarded any mobility at all, even though mobility was far worse due to physical conditions, i think I should have got high rate mobility.they wanted a face to face assessment, but i didn't attend, it was all too much, and I attempted suicide, so it was just paper based, but they ignored all my supporting documents, without my knowledge, in a form they sent to my GP for information, my GP had written that there was nothing wrong with my mobility, which was incorrect, my GP even had evidence which she ignored. I was not in any state of mind to cope with appealing their decision, and I had no one to support me in appealing, even mental health team refused to help. Renewal now, firstly, i am reluctant to give my permission for them to contact my GP, esp as now I have moved, n only been here a few months, so new GP does not know me well, but unsure what the consequences of that might be, or can I ask that if they want any data from my gp that they should send it to me, n i will pass it on to her? secondly can I state in the form that there refusal to give me mobility last time was unlawful (or something like that) and explain that I didnt agree with them, but was too ill to appeal? do you have any suggestions what to do or what to write?