Is it permissible to strive to obtain a commission for arranging a bank guarantee for a foreign company, given that the investor who will provide the guarantee will take a percentage of 10-12% of the amount as a condition, and is this commission considered unlawful money (riba)? If so, is it permissible to use it to pay off pressing debts, or what is the best way to dispose of it to avoid its unlawfulness?

What the investor did—providing an interest-bearing bank guarantee in exchange for a percentage—is unlawful (haram). A guarantee (kafalah) is a contract of benevolence (irfaq), and it is not permissible to take a fee for it. If any amount from the guarantee sum becomes due, it would then be a loan that brings a benefit (qard jarr naf'an), which is prohibited. The majority of jurists have forbidden taking a fee for a guarantee because it transforms into a loan with an increase, and the guarantee ceases to be an act of benevolence and assistance. Therefore, the amount taken from the company is ill-gotten gain (suht), and it must be disposed of in charitable causes. If someone acquired money through unlawful means, repented, and is poor, it is permissible for him to take from it what suffices his needs, and then dispose of the remainder.