Is purchasing an apartment from social housing through bank installment plans, where the apartment's price exceeds the original advertised price due to bank interest, considered forbidden usury (riba)?

Regarding the handling of the apartment price, which might increase by 10% due to delays in raw material price hikes: The fundamental principle is that the price must be known. However, if the increase is significantly detrimental to the executing party, then an increase in price is permissible, and the judge or arbitrator is the one who decides the dispute.

As for the discrepancy between the price announced in the terms and conditions booklet and the price paid to the bank, there are two scenarios: 1. Valid: The bank buys the apartment from the fund and then sells it to the client at a higher deferred price through two separate contracts. 2. Invalid: The bank finances the contract between the fund and the client by paying off the client's debt to the fund and then collecting a higher amount from the client. This constitutes usury (riba).