What is the ruling when the pledgor and the pledgee disagree on the quantity of the pledged item?

Primary text

The statement of the pledgor (Rahin) is accepted when there is a dispute over the quantity of the pledge, such as when the pledgor says 'I pledged this slave,' and the pledgee (Murtahin) claims, 'It is this slave and another slave.' The ruling favors the pledgor because he is in the position of denial (munkir). There is no known disagreement on this ruling.