I’m currently on Medicare disability. I need help changing distribution from a Rep Payee, to myself.

My sister was designated as my Rep Payee after my husband died last year. She has not been communicating with me adequately nor does she send me the mail from Medicare as she should. I’m up for review now and I’m worried that she will sabotage my case for qualifying for continued disability by not giving me the paperwork required (she already has a history of this). I need support and strong actions to force her to do the right thing and give me my correspondence with the Social Security Admin and Medicare.