Summary judgment in favor of plaintiffs, a class of Medicare beneficiaries, in an action challenging the Secretary of Health and Human Services' practice of demanding "up front" reimbursement for secondary payments from beneficiaries who have appealed a reimbursement determination or sought a waiver of the reimbursement obligation, is reversed, and injunctions entered to enjoin said practice and one that required attorneys to withhold settlement proceeds from their clients until after Medicare is reimbursed, are vacated, where: 1) plaintiff demonstrated Article III standing on behalf of the class of Medicare beneficiaries, and plaintiff's attorney independently demonstrated standing to raise his individual claim; but 2) the beneficiaries' claim was not adequately presented to the agency at the administrative level, and therefore the district court lacked subject matter jurisdiction but their due process claims are remanded for consideration; and 3) on the merits of the attorney's claim, the Secretary's interpretation of the secondary payer provisions was reasonable.