Paytm Mall - Product picked not providing replacement

I had returned two products to Paytm. One for the replacement and for refund. Both products were of the same brand and two different delivery guy was coming for pick up. But first delivery guy took both the product. When the second one arrived he told that he was assigned to pick the product for replacement. Then I've called to the first guy he said, he'll submit that product in office, there will be no issue. Now it's almost * month I've complained about it a lot. Paytm is doing nothing, return request is still showing rejected (because the *nd delivery guy rejected it, as he didn't get the product). I've explained everything to the Paytm, provided details of both delivery guy. But they said they can't directly talk to there delivery boy. And now rejecting my complaint every time I complain about it. They just give me one reason your product isn't picked.