delta store - recieved defected product through online

i bought a product (realme RMA*** Fitness Band) from online shopping store delta store(https://www.deltastore.in/) which costs **** rupees. as soon as delivery of the product i recorded an unboxing video of the product, because i hadn't purchased from the site before. and the product which i recieved was a deficit product, Which can clearly see in the video. soon after that i registered a complaint on their site, and i got a complaint confirmation mail, in which they says that their executive will contact me within ** hrs. neither of them contacted me. i have registered complaint *,* times and tried to contact them on the number given on their site, no one attended the call.