Is purchasing certain devices—like phones—in installments from a store that does not own them except by request of the buyer, then sells them to him in installments, considered a 'sale of an 'aynah' or not?

If a merchant buys the commodity requested by a customer and then sells it to him after taking possession of it, this is not a Bay' al-Inah (a type of buy-back sale), and it is a valid and Islamically permissible sale. The resolutions of the International Islamic Fiqh Academy state that Murabahah (cost-plus financing) for an ordering party is permissible if it occurs on a commodity after it has entered into the possession of the agent and been taken possession of, and the agent bears responsibility for damage before delivery and the consequence of returning it due to hidden defects, and the conditions of sale are met and its impediments are absent.