After you put any part on the market for sale, it will stay there for 24 hours.
If the part is sold during that time, you will receive a notification confirming a successful sale.
If the part is not bought by anyone within 24 hours, it automatically goes back to Storage. Therefore, make sure you have enough available storage slots for your parts to return.
If you are absolutely sure that the item was sold, email us via support@cm.games or contact using form on any page of FAQ. We'll need to know your account username and item price.