PIP Not on medication

I’m new on here and my case is a bit complex and I do have a tendency to get side tracked so please bare with me. I have been in receipt of ESA and Pip since 2013. My health conditions are Anxiety, depression, herniated disc, osteoarthritis of both knees, hips and cervical spine. COPD Labyrinthitis, insomnia, IBS, diverticulitis, tinnitus, blepharitis and most recently collagenous colitis.
I was last assessed for pip April 2019 and my high rate mobility and high rate daily was altered substantially. Mobility was stopped and daily ling reduced to standard rate. I had previously gone to appeal and won my case but at this time I could not cope with going through it all again as my mobility needs had increase and that impacted my mental state. So after going through the mandatory stage my mum who I was caring for said...don’t put yourself through this again, if you need help financially I will help you we will just continue to support each other.

Sadly my mum passed on the 16th of June 2020 holding my hand, which has impacted my mental health greatly. I previously qualified for the planning and following a rough as I am unable to go out without someone with me. My daughter moved back home to support me and does most of what needs doing on a daily basis. I do have the occasional days when my energy is little better however, on those days I’m exhausted after doing quite menial tasks.

My mum left me some inheritance which took me over the threshold for ESA. I contacted them immediately and notified them as such. My award for pip had been extended due to COVID until 2022. I still contacted them told them my mum had past and to update them on adverse changes to my health. After my flu vaccine last September I developed severe persistent diarrhoea with bouts of bowel incontinence, a long story short was diagnosed with collagenous colitis. My GP said he didn’t know what it was and that I will have to contact the consultant myself.
I stopped all my medication and told the GP it wasn’t doing anything for me. They didn’t seem to be bothered all I ever heard about was COVID.
It was noted on my previous pip assessment that I didn’t take medication for my mental health condition!
I with the help of my daughter want to sue the DWP and the NHS for neglect. My mental health and physical I’ll health has impacted me my whole life and through the negligence of both my GP practice and the DWP contracted HCP not referring to my historical case notes.
During the time my mum was on end of life care somebody reported me for fraud. I have never done anything intentionally fraudulent in my life. I was apparently putting my mums wheel chair in my car which they deemed did not coincide with my herniated disc and arthritic conditions. They also said I had been seen walking my dogs which was another lie. I wanted them to take me to court as my neighbour has a camera which they could have looked at over a period of at least one year where they would not be able to prove there findings. I was told by the fraud lady that she knew I was telling the truth. I have not been able to recover from the debilitating effects of mental illness due to the unprofessional ways in which I have been treated as a human being. Mental illness has a major impact on ones physical well-being.

I would really appreciate some feedback on whether I have a case to have my previous pip award overturned and when I phoned pip to notify them of my mums passing and my additional conditions. I was told by the lady I spoke with, that she would send a new form for me to fill out but if I didn’t want to and was happy to stay on the lower rate daily living allowance I could. She lied! Why do they do this?
Within two weeks of receiving it I got a another prompt but giving me two months to return it.
The second question: can they by law refuse me the higher rate of either daily living or mobility because I’m not taking medication which wasn’t helping apart from the inhalers which I’ve also stopped?
Sorry for the length of this.