In Desperate Need of PIP Help

I would desperately like help with PIP. I'll try to be as concise as possible to keep it simplified. My wife normally deals with all of these matters as I struggle, it takes me great effort and I become unwell because of it.

My primary health history has led to multiple secondary conditions. I suffered a prolapsed disc 2006, followed by a Brain Haemorrhage in 2007 then developed Epilepsy from 2015 as a result of damaged brain tissue. I have many other conditions as a consequence but I'll not detail everything on here.

. I have received PIP since 2015
. Reviewed 2017, Extended to 2021
. Enhanced Daily Living - Standard Mobility
. September 2020 Received a letter extending PIP award until October 2021
. November 2020 Received PIP Review Form. Confused, but completed!
. Phone assessment Thursday April 29th 2021
. Regular payment due Thursday May 27th, but only received an odd small amount
. NO LETTER, Phone Call or Text Message !!
. Rang DWP who suggest they can't access the details, but it looks like my award has stopped
. They suggest I may have received 0 points
. My wife on my behalf has told them to send the report and we will start Mandatory Reconsideration

How is it even possible for anyone to find themselves in a situation like this, but we seem to now hear or read all too often. How can I lose an award and payment without any type of notification within the one month since the review. How can all my health related problems I live with day to day disappear. How can I go from Enhanced Rate to Zero Award? I'm in a mess with anxiety already as it's a huge percentage of household income and worried about the chain reaction affecting other benefits.
I've had problems with ESA in the past, which I won at Tribunal. It took a great deal of personal effort to face these people in court as the system is broken and needs fixing. I could not have done that without support I had and fantastic help from Citizens Advice.
Now I find myself in a similar position to overturn an injustice, but not sure at all how to start this time with Covid affecting choices. I'm really sorry for adding any unnecessary detail, but I'm desperately trying to get my head around it all and take the best action.
Any help in where or how to begin would be gratefully appreciated.
Kind regards, Steve

Thank you for your reply Catherine, my wife and I will definitely follow your link to the guides. We have both been through major difficulties with the changes to my health over the years and dealing with the Benefits system has often been an absolute nightmare. There is a huge disparity between assessors with some who lack the background to understand varied health conditions and how they can affect an individual. Some illnesses and disabilities are hidden and it is often very hard to convey these unless it is to someone with the correct knowledge. Some reports you receive are insulting and border the line of utter disbelief.
I will return with an update when we find our way forward with this latest setback.
Kind Regards, Steve