ESA NI Pension Credits too unwell to fight DWP

Hi I’m new to the forum but I’m at a stage where I’m not felling enough to challenge a recent DWP decision without help and assistance. I previously worked for the Civil Service for nearly 40 years before I was forcibly retired on medical grounds. I suffer with a myriad of conditions for which I’m prescribed 13 different medications. The Civil Service pension scheme sent me for medical assessment with their appointed specialist Oh Assist who told me at the interview to stop working immediately. Their report said I was unfit to work and there were no adaptations they could recommend to make capable of performing any work in any capacity. The Civil Service Pension scheme retired me at age 55 on the highest level on that basis I would be unfit to perform any work in the future. I was reviewed again at 60 with no change in their assessment. I was also in receipt of PIP and last month I was awarded higher rate for both care and mobility without any end date. I’m not in receipt of ESA or UC or any other means tested benefits because of the level of Civil Service pension. I did the on-line Govt Assessment when I retired and it confirmed that I wasn’t entitled to claim anything else except that my wife was entitled to claim Carers Allowance. It wasn’t until a few weeks back that I discovered that I wasn’t entitled to a full state pension because from 55 onwards I hadn’t made NI contributions. Because of the looming deadline to purchase extra years I had to use my £5K savings which were put aside to fund a stair lift. An Adult Social Care report said I was at considerable risk using the stairs but wasn’t entitled to a means tested grant. Sadly now my savings have gone and I am still short by 2 years of a full state pension. The chap at Inland Revenue asked me why I had not claimed Pension Credits which totally floored me as I wasn’t fit to work. I told him I looked on-line at the time I retired and the available advice was I wasn’t entitled to any means tested benefits and there was no mention of an entitlement to pension Credits. It transpires that even though I worked enough qualifying years because of changes to SERPs legislation i.e. I was unaware II had been contracted out my Employer had only paid contributions to my Civil Service and pension and not to National Insurance. I contacted DWP about 2 weeks ago and explained that I wanted to claim for Pension Credits and have them backdated to when I was retired. The DWP said I needed to put in writing why I didn’t claim previously and get my Gp to write a letter to say I wasn’t fit to work the last 5 years and in the future. I was shocked by the request and said my GP wouldn’t provide such a letter as most of them are new and their GP records didn’t even have the correspondence when I was medically retired. All I could provide would be the final OH Assist report that formed the basis of my medical retirement and also a copy of the Gp letter that went to the Vibil Service pension scheme when I had my review at 60. The DWP representative said he would send me a text with a link to upload the evidence and he would call me a week later on Wednesday to see how I was progressing. I received no text message and no phone call on Wednesday (this week just gone). This morning however I received a formal letter from DWP saying “We cannot pay you ESA from 1 Dec 2022. We cannot pay you because you have not paid , or been credited with enough National insurance Contributions. …. you may need to attend a Work Capability Assessment. You must provide Medical certificates until a Work Capability Assessments is carried out. To say I was shocked, confused and disappointed was an understatement. I don't have the energy or the capacity to fight this. I suppose the staff in the DWP are totally disillusioned with their treatment by this Govt and have given up with supporting the Public unless forced to do so.