URGENT help Nikolai access vital records

Hi there I feel super self conscious and embarrassed doing another fundraiser but this one is really urgent. Lewisham council did not tell me I needed to keep all of my direct payment records for several years and I was homeless and then moved cities so I lost a lot of information. They also never asked for monitoring forms. Now they want all of the evidence or they want me to pay over £21,000. I am on benefits and disabled and can't even imagine having that sort of money. Now, my old payroll company have all of the records of how I spent the money. but won't release it without a several hundred pound fee. Lewisham are refusing to pay it. I need all the records by the 14th so they have them by the 19tj or it'll all be sent to debt collectors. All of this is having such a bad effect on my mental health and I am terrified of being made to pay money I can't afford and shouldn't have to pay. Please help if you can