Myntra - Got wrong product in exchange for different size

I ordered a "Levis jeans *** straight fit" on ** dec.**** delivered on ** dec. but got issue with size so I place exchange request for one size up (larger) on ** dec.**** which delivered on ** dec. but what I got after exchanging Is jeans of different style (bootcut instead of straight fit) of same brand with too large size (i wear ** size but got **) which is of no use of mine even if I wanted to compromise.
I contacted customer care but they are refusing to return by stating that they have sent correct product.i have shared images as evidence but not getting any satisfactory responses.it might be because the polythene (inner bag of main ) bag is showing size ** but inside product was of **size .so,there is chance that they put wrong product in the poly packet of some other original product (they asked me serial number written below bar code.so,i am assuming that).here is my loss as they are claiming that there is no mistake and they have sent right product but i got wrong one.
I don't know what to do now.its depressing.I usually don't complain.i have complained * times since i have started using myntra for wrong product but *st time wasn't that hard.this time i have complained * times (*st on **dec,*nd on *jan. And *rd on **jan.) But not getting any satisfactory responses.everytime they closed my complaint without notifying me on mail or sms on registered number
The total amount is **** for the product which is a big amount for a middle class.i rarely buy something that costly.it is no use of mine or i could have keep it.i am concerned about my refund