seller

Q: Is it permissible for a seller to fight with a person for an amount of 1 lac because the purchaser does not want to pay the remaining amount of a property purchased due to some reason. Is this amount halaal for the seller or not?

Q: I run a business buying and selling furniture, gold and silver. When a person sells an item to us, then in most cases, an option is given to the seller to buy back the item sold at any time, if still in stock, but at a higher price. Is this permissible?