Is it permissible for me to take a sum of money belonging to a runaway worker about whom we know nothing, and deduct it from my large financial entitlements owed by the company, which is procrastinating in paying them?

It is not permissible to take the aforementioned money as compensation for a right. If the money belongs to the worker who left the job, it must be returned to him or given in charity on his behalf. If the money belongs to the company, it is not permissible to take anything from its funds without permission, unless the right is withheld, and all legitimate means have been exhausted, and the right has not been granted. In such a case, it is permissible to take an amount equivalent to the right, according to the principle of "al-Zafar" (gaining one's right by force when denied).