HDFC Bank — Refund amount not credited

I have purchased a mobile from amazon.in on march2020 on emi basis. On apr2020 and may2020 they have collected rs9590.67 and rs9834.49. Due to lockdown the delivery of item is delayed and hence i cancelled the product on may18. They have accepted my request and refund has been initiated and have provided refund reference number#3548891. Till this date, refund has not been credited in my account. Kindly look into this matter and do the needful. Delayed payment will attract interest @18% or rs100/day.
Copied to ombudsman trivandrum

Manu krishna