GI24 form

Anyone know if you can download this form to send or if they will accept a letter with relevant information on. I first asked for the form to be send on the 10th of June (date of decision was 6th June) and despite 2 more calls I still haven't received the form and I know I have to send it within a month so I'm fretting a bit.

Also, despite me being unable to work, I have M.E/C.F.S as well as other conditions they have suggested I claim JSA, is this possible when I know that I am not capable of holding down a regular job because of the illness?

Thanks in advance