I bought apple airpods pro 2nd generation from Flipkart but when the airpods arrived their serial number was mismatched. So can you give me a job sheet or denial letter regarding it

You have posted to a forum where Apple users help other Apple users with technical issues. We cannot provide a job sheet or denial letter. It sounds like you need to return those to Flipkart if you are not happy with what you received. FYI, the left and right pair each have their own different serial numbers.