Is it permissible to deposit a sum of money into an account to obtain higher-value products and thus a greater profit, and is working for this company lawful or unlawful?

The ruling on this action is based on two matters: The first pertains to the advertisements themselves. For them to be permissible, it is stipulated that the products must be permissible, and there must be no deception or fraud, due to the Prophet’s (peace be upon him) saying: "Whoever deceives us is not of us." The second relates to the purpose of placing and depositing the money. If it is merely for guarantee and the company does not benefit from its retention in the account, then there is no harm. However, if the purpose is for the company to benefit from the deposited money, then this is not permissible, because the transaction involves a loan that brings benefit, which is usury (riba). The participant pays money to the company for it to benefit from, and this is considered a loan, and in return, commissions increase according to the deposited amount. Furthermore, stipulating a loan contract along with a marketing contract is not permissible.