What is the recourse if the deposit was a debt (dayn) and the principal later denies the agency and claims the debt back?

Primary text

If the item delivered was a debt, recourse is solely against the original payer, because the debt in the payer's liability was not discharged by delivering it to someone other than the creditor's agent. The agent and the payer both claim that the debt was transferred to the principal's ownership, thus making the agent an oppressor against the payer by taking it. Therefore, the payer may reclaim what was taken by the agent, treating it as retribution for what the principal took from the payer.