Myntra - Return Packaage pickup not being done

I ordered a product on myntra, which was delivered to me on march **, ****. The same day I raised a return request through customer service, as the product was in damaged condition. The return was approved, however, I received mails hat the return has been cancelled by the courier, the reason being given as "We were unable to pickup your return order. This may have happened if our associate was unable to reach you or you requested for a reschedule." But none of these happened as there was no call from them. I again had to raise a request and it was not picked up again (it was showing in the app as out for pickup on Mar ** - **). Following which i called the CC but they told me to wait for * days as that is the norm for returns to be picked up. But today (Apr, *) I got a mail saying that i have to self-ship the reason given as "pin code is not serviceable for pick up". I was pretty surprised on that because I returned a product just a day before (although different account but from the same address), also I had a few recent instances were the return were picked up from this address. For checking this I called the CC again (to be specific i have to place a call back request in the app.), the agent just read out the same thing again to just addind one word 'apologoes', when i asked for a reason he repeated the words again. Then I asked for a supervisor/manager, whom I can speak to, he placed the call on hold twice and came back saying no manager available on the floor. I asked him raise a callback request, they don't have an option for that as well. This was a very bad experience. Anyway, the primary objective here is why it was not picked up?, what is the exact reason that i have to self-ship (as other orders from myntra are being picked up smoothly)?, It should be picked up by myntra and provide a refund on this.