Question Summary:
Is agent to sell liable for the destruction while the item was in his possession.

Question Detail:

Someone gives me a car to sell. I park it outside my home with the FOR SALE sign. A customer comes to see the car and unfortunately I misplace the key. Now, who is responsible for making a new key?
Is it my zimedari or the owner should make a new key?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
In this transaction you are Wakīl bil Bay‘. While the car is in your possession, it is in the ruling of Wadī‘ah (Safekeeping). This means that it is an amānah in your hands. If the car or any part of it is destroyed due to negligence from your side, then you will be responsible. However, if there was no negligence from your side, then you are not responsible to cover up the loss.[1]
 And Allah Ta’āla Knows Best
Mawlana Faisal bin Abdul Hameed,
Student Darul Iftaa
Montréal, Canada