Sorry, you're not eligible for ESA from two weeks ago but we're only telling you now

Hi everybody, I've got a bit of a problem. I was on ESA (WRAG) after winning an appeal, but I missed a medical appointment because I didn't get the letter to tell me that I had one. They sent me a slip asking why I didn't attend but I just wrote that I didn't know I had one. Obviously, I didn't include any proof because I didn't have any.

So I got a letter dated the 29th of April (didn't get it until 2-3 days later) saying that I was found fit for work from the 13th (the day after the medical that I didn't know about).

So I don't really know what to do now. CLAC has closed down and the CAB just referred me to the council to ask for an emergency loan, but I don't need a loan, I need an income. I tried to claim JSA (as advised on the letter) but I couldn't without declaring that I'm fit for work.

I've got a sicknote dated from the 13th but I don't know what to do with it. Should I make a new claim for ESA or should I appeal the decision/ask them to reconsider? There's a big gap in my payments (last payment was the 19th of April) and I'm right into my overdraft now, so would they backdate it to when they stopped it?

I'm really worried and I don't know what to do. There's no help out there anymore :(