Is it permissible to join a gold selling company that grants continuous profits (according to its sales) to buyers who bring six other buyers?

It is not permissible to participate in companies based on pyramid schemes because they involve gambling, unjustly devouring people's wealth, and deceiving them. If the company sells gold, it is not permissible unless the gold and the price are exchanged in the session of the contract, due to the Prophet's (peace and blessings be upon him) saying: "Gold for gold... hand to hand." It is also not permissible to sell gold in installments.