Selling something that is non-existent at the time of the sale
Q: I sell eggs and I keep my stock at my parents’ shop. Once, a staff member from my parents’ shop had taken from my stock which is kept separately and sold it to the customer. It was brought to my attention a while later. As the products were more expensive, I had discounted them when sending the invoice although the goods had already been sold to the customer. Is this permissible?