Hi samkajo
I can't be certain here, but a lot of people have found that they have been moved onto new style ESA as well as universal credit, and yet this information comes out later. Now I could be wrong - but I offer it as a possible suggestions - so you might want to query it.
I'm sorry this is happening to you. Hang in there and ask in your journal
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems