Is an employee who has retired entitled to receive a sum from a social welfare fund after discovering that the fund's money was deposited and invested in an interest-based (usurious) bank?

"There is no harm in taking what has been deducted from his salary. However, it is impermissible to take the usurious increase. Rather, it should be withdrawn and spent on Muslim welfare or given to the poor and needy. A poor person in need may take from it what suffices his need. The subscription contract with the fund must be terminated if it is still ongoing, because it is prohibited."