Is a merchant's act of purchasing goods for a customer and then selling them to him in installments with a 2% monthly increase considered usury (riba)? If it is usury, is it obligatory to dispose of the goods purchased in this manner after repentance? And what is the Shariah ruling on this issue?

If a merchant purchases the desired commodity and takes possession of it, then sells it to a customer in installments at a price higher than its current cash price, there is no harm in that, provided that the price is agreed upon and the contract is concluded based on it, without the price being subject to increase due to delayed payment, as this would be prohibited usury (riba). However, if the merchant does not purchase the commodity but rather lends the customer its price and is repaid with an increase, this is prohibited usury (riba).