What is the ruling on a civil engineer taking the difference in price between two material suppliers, while presenting an empty invoice to determine the price he desires, knowing that the company wrongs him in some allowances and bonuses?

This act is a form of lying, cheating, deception, and unlawfully consuming people's wealth, as the Prophet, peace and blessings be upon him, said: "Whoever cheats us is not of us." What you are doing is a betrayal of trust and a violation of the fatwa issued by the Permanent Committee, which prohibits lying and taking people's money without right. The company's refusal to increase your salary does not permit you to deceive it and unlawfully consume its wealth.