Is it permissible for an employee to take an old and unused device from their company as compensation for their unpaid financial dues?

If you have an established right with the company, and they refuse to give it to you, and you are unable to obtain it except through a ruse, there is no sin upon you in doing so, provided that the device is equal to or less than your right, based on the issue of al-Zafar (taking one's right by force or stratagem) in Islamic jurisprudence. However, if you do not have a right according to the contract, or if you are able to obtain your right through legitimate means, then it is not permissible for you to take anything from the company's property without their permission. Rather, you must return the trust, as the Prophet, peace and blessings be upon him, said: "Upon the hand is what it has taken until it returns it."