The recourse is to sue that's how you recover money that another party owes you pursuant to  contract and/or for work you did and which they do not pay you. Even if the agency is telling the truth about delays in them being paid, or the wrong amount being paid, etc., that is not a defense they are still obligated to pay your daughter for her work even if they are not paid by their own client. If not paid by their own client, they, in turn, could sue the client. So if they refuse to pay, you can sue them for the money you would sue based on breach of contract.