Is money considered unlawful if the bank loan is not repaid after termination of employment for no reason, and must it be repaid?

It is not forbidden to benefit from money before paying off a debt. Your dismissal from work does not nullify the debt unless another party pays it off or the bank absolves you. If the debt is to a usurious bank, you must repent from it and pay only the principal amount of the debt. You are not obligated to pay the usurious interest unless you are compelled to do so. However, if the debt is to an Islamic bank, you must pay both the principal and the profit. Your dismissal from work does not nullify the debt, and one must be cautious about being negligent in repaying debts. Whoever is unable to repay with good intention, Allah will assist him or pay on his behalf. Whoever takes people's money with the intention of repaying it, Allah will enable him to repay it. And whoever takes it with the intention of squandering it, Allah will squander him. As for one who dies owing a debt and was unable to repay it, his soul remains suspended by his debt until it is paid off on his behalf.