What should I do about the contractors' money that the manager takes, especially since my conscience is uneasy about his actions, so should I inform the contractors of the correct amount?

It is forbidden to consume people's wealth unjustly, as Allah Almighty says: "And do not consume your properties among yourselves wrongfully." This includes usurpation, theft, treachery, and taking wealth through unlawful exchanges like usury and gambling, as well as cheating in buying, selling, and renting, and consuming workers' wages or not completing the agreed-upon work. Therefore, it is not permissible for the questioner to comply with his manager's order, which involves consuming people's wealth unjustly, as Allah Almighty says: "And cooperate not in sin and aggression," even if it leads to his dismissal.