I work in the post office and overcharge the clients. For example, if the cost of sending a letter is 1.5 dirhams, I ask the client to pay 2.5 dirhams and so on. Can I take these additional dirhams or not?
It is not permissible for you to deal with people or charge them more than the amount stipulated by the postal service and all the received amount of money is the sole right of the concerned authority. You should only get your salary for doing your job. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.