Instagram Seller (amazon_online_seller_) — didn't get product after payment

I had order a phone from a Instagram seller @amazon_online_seller_ on 16th April 2019.He asked for full advance payment I gave him i.e. 10k. He said I will get my product in 3days, after 3days I text him he didn't reply I also tried calling him but he doesn't pick my calls. After sometime he blocked me on Instagram. After that I tried to reach him on WhatsApp and ask him for my product, he again stared ignoring me. Atlast I said I'm going to file a case against you.. he said do whatever you want. I have got all the screenshot of the conversation and payment details. Please help me