Many buyers who make this kind of demand will likely charge back even if #1 ranking staus is attained, because not only is there no way to guarantee that rank, there is no way to guarantee it stays there. Either way, the buyer can claim the seller didn't deliver, charge back, and the provider is robbed of their time and labor. So a seller should only answer this if 1) they get paid by BTC or other non-refundable way, or 2) the money is placed in escrow, and paid at the end. If the OP will work with either of those options, PM me.