Flipkart - Invoice without IMEI number Flipkart Flipkart

I had purchased google Pixel *A from Flipkart on **th November **** the invoice that I have received from Flipkart does not have the IMEI number of the phone that I have purchased rather has the IMEI number of my exchanged phone Oneplus mentioned due to which I am not able to get my phone repaired under warranty as the Invoice isn't valid ,there is only * months left for the warranty to get over and I have complained Flipkart about the same multiple times but they have not provided me with any solution yet.I also got a defective phone and every time I had a conversation with Flipkart they are unable to provide me a valid invoice with correct IMEI number mentioned on it and on top of that they are asking me to provide the IMEI number which totally implies that they don't have the IMEI number of the phone that they have sold and which is completely unethical and illegal.This also means that the phone could have any criminal history or procured in a illegal way which in future can put me into trouble as I don't have a valid proof for the device that I have purchased .This has wasted so much of my time and efforts everyday that right now I am using an old phone which is too hard to work with my professional work is based out on phone calls which has been highly affected and my productivity has also been hampered .