RDX Accessories - Received internally damaged product without bill

I purchased a pair of Skullcandy earphones (Model - S*IKDY-***) from RDX Accessories which is located opposite TCS Gitanjali Park, Beside, DLF * Rd, AA II, New Town, West Bengal ******. The shopkeeper sold it to me without the bill, and on asking for it, he said that he will send me a soft copy of the bill which he didn't. The earphones, according to the seller had a warranty of * months but it stopped working within ** days of use. When I approached the seller to resolve the issue, he blamed me for damaging the earphone, but there has been no external sign of damage to the earphone. He sold me an internally damaged product without the bill which he claims to call within warranty period, he is blaming me for the damage and now is asking for more money to repair/replace the earphones.