Is it permissible for the company to deduct the cost of training courses from the salaries of employees who resigned due to delayed salaries, while requiring them to benefit from certificates that may not be useful to them in the future?

The company is not entitled to deduct the price of the lectures from the salaries of employees whose resignations have been accepted, unless this was a stipulated condition for them. The company has the right to reject the resignation if the contract period is still valid. As for the course that the company provided for the development of its employees, it is not permissible for the company to take its value from their salaries, because Allah (Glorified and Exalted be He) says: "O you who have believed, fulfill [all] contracts," and because the Prophet (peace be upon him) said: "Muslims are bound by their conditions," and "The property of a Muslim person is not lawful unless given with his willing consent," and "Give the laborer his wages before his sweat dries." And it was stated in a Hadith (definition) Qudsi: "There are three whose adversary I shall be on the Day of Resurrection: a man who gave by Me and then betrayed; a man who sold a free person and consumed his price; and a man who hired a laborer, benefited fully from him, but did not give him his wages."