Iphone shop froud

I ordered an iPhone 17 Pro through the OLX app on EMI. The shop seller told me that my EMI would be done for Rs. 6,000, so I paid Rs. 6,000 as told. After this payment, they said the EMI would not work with Rs. 6,000 and that it needed Rs. 10,000. I paid an additional Rs. 4,000 to meet this new amount. Then they again changed their statement and said the EMI would not work even with Rs. 10,000, and demanded Rs. 28,500 more to complete the order. At this point I told them I did not want to continue with the order and asked for my money back. However, they refused and said no refund would be given. I am now demanding a full refund of the amount I have already paid, since the seller kept changing the EMI terms and is now denying my refund.