Flipkart — received different model product from flipkart

Address:

West Godavari, Andhra Pradesh

I ordered redmi note 5 pro - black 6 gb ram on 3rd july, it has to be delivered on 9th july as promised by flipkart but delivered on 11th july. I don't know what happened in between those dates and found the different product (Redmi note 4) when i opened flipkart parcel box. And also i couldn't see return option after delivering product. I spoke with flipkart agent and risen the complaint regarding. Till now the problem not yet resolved and also they asked me time for investigating i reverted them that i'll be available for anytime for giving any sort of information from my end. They investigated the issue and promised that they will be giving replacement on or before 30th july, 2019. Again on 29th july they have cancelled their replacement request and again they are asking to wait till august 5th to receive my ordered product. Its been a month they are playing with me. I have already paid the money as it was cash on delivery order. Please look into this issue and give me resolution for this issue.