What is the ruling on changing the method of calculating the cost of maintaining an electronic device for a customer—by mentioning the cost of materials at a higher price and labor at a lower price—in order to guarantee the full retrieval of the deserved payment?

One of the conditions for the validity of ijara (leasing/hiring) is the determination of the wage/rent at the time of the contract. If this condition is not met, the ijara is invalid, and the worker is entitled to a fair wage (ajr al-mithl). Lying or cheating in determining the cost and wage is forbidden and causes the removal of blessings, based on the Prophet's (peace be upon him) saying: "The two parties to a transaction have the option (to annul it) as long as they have not parted. If they are truthful and clarify, blessings will be bestowed upon their transaction. But if they lie and conceal, the blessing of their transaction will be removed." And his saying: "Whoever cheats us is not of us." Truthfulness in dealings has a great reward, based on the Prophet's (peace be upon him) saying: "The truthful, trustworthy merchant will be with the prophets, the truthful ones, and the martyrs."

The correct approach is to inform the customer of the truth, that the wage is twenty pounds, or to contract for forty pounds with the cost borne by the worker.