Myntra - Wrong product delivered and refusing accepting returns

I have received a totally different product from the one i actually placed , as soon as i opened up the package and found that the product is wrong , i immediately kept it in the same condition aside and requested for a return . Next day the courier service provider came and picked up the package and after an hour i got an SMS on my registered mobile number that my return has been kept on hold as the product doesn't meet up to the requirements . I contacted the myntra customer care right away and they asked me to wait for a response . Now in response they are asking me for the pictures of -
Billing details/ Invoice
Product
Packaging
I would like to know of how can i possibly click pictures of these things when my package is already with the courier service providers and also i have no clue which courier service provider it is . In their mistake and zero sense of responsibility , why i am being troubled . Why would i return it in the first place if they would have given me the right product . I want my refund back and no help is being provided on their behalf .