What is the ruling of Islamic law on changing the mileage on a company car designated for work to avoid salary deductions, and on using company property (such as stationery) for personal purposes, especially given that the company is American and spends extravagantly on such matters? And how can one atone for this in the past?

The employee is obligated to be honest and fulfill the terms of their contract in their work. Therefore, company property, such as stationery and the company car, must only be used for what is permitted. Personal use of the car must be recorded. It is not permissible for an employee to cheat or betray, even if the company is not Muslim. Atonement for past actions is achieved by seeking forgiveness from an authorized official in the company; otherwise, the value of what was taken must be paid. If the employee fears harm, they should return what they took without informing anyone, based on a predominant assumption.