Is it permissible to sell furniture in installments through the bank, taking into consideration that the bank is the one that collects the monthly installments from the customer in a country where there is no guarantee for the retrieval of money?

The aforementioned transaction is incorrect, whether it is selling the debt to the bank for a lesser amount to be collected in installments, or your agreement with the bank to pay on behalf of customers for an immediate price and collect from them with an usurious increase. Both scenarios constitute forbidden usury (riba) and cooperation in sin. Instead, you can take checks from the buyer, request a solvent guarantor, mortgage an investment deposit, mortgage movable property or real estate, or mortgage the commodity subject of the contract.