بسم الله الرحمن الرحيم
If the shopkeeper deals it directly not through a bank and at the time of dealing the total price of the goods and the duration of installments is fixed then it shall be lawful to buy the goods in installment. Hence in the question mentioned above you may buy the goods in installments from the shop while maintaining the above mentioned conditions.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.