What is the ruling on purchasing a check for a symbolic amount from someone who has despaired of collecting its real value from a dissolved company?

Buying a check with cash is considered a form of currency exchange (musarafa), which requires immediate transaction (munajaza) and equivalence (mumathala) when the two currencies are of the same type, and only immediate transaction when they are of different types. This scenario is invalid because it involves usury of excess (riba al-fadl) and usury of delay (riba al-nasi'ah), as well as gharar (definition) (ambiguity/risk); because the buyer paid less to receive more of the same type after a period of time, and the check may not be collectible.