Flipkart - Wrong product delivered but no replacement or refund after 12 days

I have ordered Realme XT (*GB RAM, Pearl white) on *st October by exchanging my old lenovo k* note and I received the product on *th October. But they have sent me Realme XT (*GB RAM, Pearl blue). I have raised request for that * times but every time the seller rejected the request by replying that the reason is not correct. I talked to the customer care executive and they are just extending the timeline. They just kept on saying that the problem will be resolved. From *th October I have been waiting to get a replacement but neither the customer executive nor the seller is helping me out. I also made a refund request on *th October but it's still pending. The return window closed on **th October but they are not taking any action to resolve the issue. I called the customer care for more than ** times but no sign of positive response. Everyday, they gave a specific time and date of resolving the issue but that timeframe is again updated and moved to a next date. From *th October, they are just extending this timeframe. Please look into this matter and resolve the issue with a higher priority.