Refused paper based pip renewal assessment despite extreme distress

Hi, I was more or less bullied into attending my first and only pip assessment a few years ago and found it si distressing l self harmed before and after (I don't use anything I scratch/bite myself when under extreme distress). My mobility payment was completely cut even though I have ptsd adhd and sciatica but too distressed to appeal. I decided never again would i put myself through that Now I've been told for the renewal I have to have an online video assessment (as I refuse to give my phone number). I managed to get the courage to call them and challenge this, since then things have worsened as my dad who was my only close family passed away in September also I have metatarsalgia which affects my mobility. The lady on the phone was really sympathetic when I explained about the self harming and said she would request a paper based assessment, but I had a letter through yesterday saying no they will be sending me another appt. Since then I have had several panic attacks and keep shaking. Can I stall them whilst I get a doctors letter as they don't know about the metatarsalgia? What else can I do? This is inhuman. Also when they refused my mobility they said if I was too distressed to travel except by cab it was up to me to fund these journeys as that was not what mobility allowance was for. I'm sure I have read different.

Thanks Gordon. I spoke to them again today and she discussed it with her manager and made it clear that I was too disressed for any type of assessment. They have cancelled both appointments and neither counts as a refusal to attend. I am also seeing the doctor on Monday and will get a letter of support.