Negotiating payment amounts on a valid debt

by Geoff
(Nassau County, FL)

My son defaulted on an auto loan and his vehicle was repossessed. A collection agent is now hounding him for the alleged difference between the two amounts but it exceeds the original purchase amount of the vehicle. He is not disputing the debt but has limited income so he wants to negotiate a payment amount consistent with his income. The collection agent is refusing to work with him and is now contacting his new employer against his wishes. What, if anything , can he do to arrange a payment that won't make him homeless?