Is subscribing to the National Fund, which requires paying 750 EGP for the subscription and then 7 EGP monthly in exchange for receiving 40,000 EGP upon retirement or death, permissible or forbidden, knowing that the money is saved and invested in banks?

Participation in this fund is impermissible due to its inherent ambiguity (Jahalah), as a participant might pay more than they receive or vice-versa, and they might pass away shortly after joining, thus becoming entitled to the sum. Furthermore, the fund's assets are invested in interest-based (riba) banks, which constitutes cooperation in sin and aggression, forbidden by Allah Almighty in His statement: "And cooperate not in sin and aggression. And fear Allah; indeed, Allah is severe in penalty." (Al-Ma'idah: 2).