Abuggy com - Duplicate product received

I bought a branded Sennheiser CX ***S wired In-ear Headphone with MIC from this new website first time, as it was not available in any shop near me or any leading & trusted website. All seemed to me fine, I called the customer care before to check if it is approachable. Then I ordered on Cash On Delivery. I received the product exact & it seemed original to me, except the sound. Still I assumed it original due to appearance. However, when I checked it directly with the Customer Support of the brand over email, the confirmed me that the product is NOT ORIGINAL and pointed out the differences between both (conversation attached). But it I have been complaining from many days and still there is no pick-up or refund to me. Therefore, I want to file a complaint regarding the same. Please also note the invoice that they have given me doesn't includes GST NUMBER, hence they must be somewhere escaping from giving the taxes also. Please resolve this as early as possible and get me my hard-earned money. Also, do keep a check on Duplicate Sellers as they may hamper India's ambition of Aatmnirbhar Bharat.

No concrete reply has been given yet, only excuses and the product has NOT been picked up till now (neither refund deadline communicated). Multiple calls with them, but everytime answer is "getting it done today".