try reporting it to your bank. Since you made the INR deposit, they may help you with a dispute. Explain that you have paid for digital goods and not received the product from seller.
If the seller is questioned, he has to provide proof.
No other way, apart from physically catching the guy and shaking him up.
i think complaining someone that i sent money but for bitcoins and he/she not gave bitcoin is not accepted. because you have no proofs that you didn't got btc.because its very simple to create btc wallet in just sec.so i think no one gonna take inquiry specially in india.
so finally you can get information of that person by bank detail and have to attacked him without help of police.