Mobile_storeapple - Duplicate items sold

Purchased an Iphone X from the online partner on **/**/****. Paid Rs *****.** by Paytm to the store. The company deals in iphones and sell on Instagram. They made false advertisements that the phones are original and they are giving the phone in special price as they have tie ups. Ultimately received the phone on **/**/****. The phone box was not sealed and the phone is defective as it is not recognising sim cards even. It is a fake cheap chinese clone and is no where near the advertised product. They are not willing to refund my money. Please help.