ESA re-assessment nightmare

Having won an appeal against being placed in the work related activity group a number of years ago, I was placed in the support group. I have suffered from and been treated for COPD, anxiety and depression for many years. A relative helped me complete the ESA 50, and I was required to attend an assessment. The original venue, near my home, was further from the car park than I could walk.
I requested another that was further away but looked more accessible. I explained the only person who could accompany me would need 1 month's notice (lives over an hour's drive away and has committments).
The appointment arrived for 9 days ahead....Impossible. The next appointment was no better, with similar time scale.
Rather than rearrange, we went. Due to my overwhelming anxiety, my friend went to book me in and asked if I could remain in the car
The answer was no. My friend came back to tell me the bad news that I would have to sign in, wait in a crowded waiting room, running 1.5 hrs late. I was in a state of panic.
I couldn't walk far enough to go with my friend to park the car and the disabled spots nearby were all taken due to the delays.
The accessibility was a long ramp or short but steep stairs. I need help with either option. So I was left crying and shaking outside whilst my friend parked up.
When we got in, I had to fill in a form, shaking so hard it was barely legible. I couldn't go into the main waiting area so sat near the door. Weeping. After 10 minutes or so a lady asked if we would come to the desk and told us my file hadn't been sent to them, and they had tried to ring me (It was stated on my ESA 50, I don't answer the telephone if I don't know the number.) I was devastated that the lady said another appointment would be sent out. I'm in a state of shock and don't know if I could face this trauma again. I thought files were electronic now! It all seems so cruel but I haven't the energy to do anything about it. Sorry this is so long, I just needed to get it out!

Thank you for your advice Gordon, I am still shaken by yesterday's events, and received the cancellation letter today. The only contact details are a job centre plus number and an address on the envelope in case of it not delivered. The address is Summit House, Nottingham NG8 6PX.
Could you advise if this is Maximus please? Do Maximus do all the assessments?

Thank you so much!

So sorry to hear of your ordeal.
It may be worth your while requesting a home visit for your pending assessment . ?
I know these are few & far between but nothing wrong with requesting this considering your difficult circumstances & especially with what you have already had to go through.
Hope it all works out for you.