What is the ruling on money acquired from selling foreign currency for Algerian dinars, where the receipt of one of the two عوضين (countervalues) was delayed, and do the mentioned justifications for the delay prevent falling into riba al-nasiah (usury of delay)? What must be done if this usury occurs?

Possession must take place at the contracting session when selling different currencies, whether it is actual possession through physical exchange or constructive possession such as immediate deposit into accounts. This is because currencies are subject to the same rulings as gold and silver regarding the necessity of possession when the types differ, and the necessity of equality and possession when the types are the same. Delay or deferred possession is not permissible. If it is possible to rectify previous transactions, that must be done. Otherwise, what has passed before knowledge of its prohibition is hoped to be forgiven.