I assume that you agreed to take in your grandmother based in part on the assurance of the weekly payment. Unless your aunt is claiming that you are not providing the promised care or are somehow not living up to your side of the bargain, you are entitled to be paid. Your aunt might be worried about the payments being construed as transfers for purposes of Medicaid eligibility for your grandmother. But they should not be since you are providing value in exchange for the payments.
I would assume that the elder law attorney would agree. You may want to ask your aunt to keep the payments going until she has the meeting rather than withholding them until then. You also might ask to participate in the meeting.
For more about Medicaid's rules, click here.