Mack2Cart — received wrong phone

Address:

Shop no-17,saket block,mandawli, New Delhi, New Delhi, Delhi, 110092

I bought a phone (Mi note 7 pro) from[protected] using olx web site. But when i received the courier and open that i found the itel company phone. But i order the other phone (Mi note 7 pro).
I payed 16500 on cod.
Firstly she told me that i have pay 500 by paytm on her bar code. I scanned her given bar code and sent the money. After some time she gave me the tracking id[protected] and the courier site address (https://www.delhivery.com/).
Thats why i did trust on her. When today (25/05/2019) courier boy came to give me the courier i called her and she told me to get the box and pay the amount. If there is something wrong inside the box than we will help you. After all this, i called her and told all this thing.. She told me that if you want to refund back than give us your bank details and we will refund you or if you want to replace it than their boy will come with new phone and replace with it. She sent me a gmail ([protected]@gmail.com) regarding the replacement of the product.
Please help me to receive my money back.