Is it permissible to buy by proxy and sell to another party, and is it permissible to profit in exchange for a guarantee or warranty, and is it permissible for a customs broker to profit from securing an import license if another person performs this part of the work?

It is permissible for an agent to sell his principal's goods to another person whom he has authorized to purchase, just as a guardian may sell the property of one orphan to another, or a father may sell to his two young children. As for guarantees and sureties, it is not permissible to take a profit or fee for them, because they are acts of kindness and benevolence, and it is not valid to take compensation for that. Customs clearance and securing import licenses have the same ruling regarding the permissibility of taking a fee for them, unless one of them requires expense, effort, and travel.