What is the ruling regarding the delay in the response from the concerned authority to a request for the handover of a computer that has not yet been delivered after the employee left work, and what should the employee do in this situation?

You erred by traveling with the device and not returning it. You must repent, for "the hand is accountable for what it takes until it returns it," and "return the trust to the one who entrusted you, and do not betray one who betrays you." Since its owners have not yet responded regarding the return of its value or forgiveness, take the initiative to clear your conscience by returning the device in its condition or its value immediately. For clearing one's conscience and returning rights is an obligation among the conditions for the validity of repentance.