Is selling a household appliance company to employees in installments, with an increase over the cash price, considered usury (riba)? And what is the ruling on the 5% commission that the collector receives for collecting the installments and remitting them to the company?

If the contract between the government company and the home appliance company is one of mediation, then it is permissible brokerage. The supply commission that it takes in exchange for deductions from employees and supplying to the home appliance company is permissible. There is no harm in increasing the price in an installment sale over the cash price.