Praise be to Allah.
In several answers we have already stated that it is haraam to deal with multilevel marketing schemes (or “pyramid schemes”) that charge a fee for joining or stipulate that one must buy a certain product in order to be able to engage in marketing and take commission, because that involves ambiguity and gambling, and because in this case the item or product is not what is sought; rather the aim is to join the marketing scheme in hopes of getting a lot of commission.
The reason why it is gambling is that the participant pays a joining fee or pays the price of the product in the hope of being able to attract customers and get commission, which may or may not happen, hence this is gambling.
With regard to permissible brokerage or agency services, that does not involve stipulating a condition that a joining fee must be paid or an item must be purchased before agreeing to act as a broker or agent.
And Allah knows best.