Is it permissible to sell an invoice to another company to demand payment when a 0% late payment interest rate is specified, and the second party delays payment, causing harm? Is the amount added for late payment usury (riba) or a disciplinary fine (ta'zir)?

It is forbidden for a creditor to impose a financial penalty on a debtor who is late in payment, because it is a Riba (usury) of Jahiliyyah (pre-Islamic era), and this condition is void and impermissible to fulfill. Likewise, it is not permissible to sell a debt invoice (sukuk) if the debt is in cash and sold for cash, because it constitutes currency exchange with deferment.