Myntra - Serial number not matching during return pick up

I placed an order on Myntra on **th may worth amount Rs ***. The product was delivered on *st July (after more than one month) . I placed a return request on *th July.
My return pickup failed because the "SERIAL NUMBER WAS NOT MATCHING" on **th July, **th July, **th July, **th July. Everytime i called them they asked me to wait for *-* days. On **th i called them and they asked me to send photo of my order and everything. Now they have placed a return request for *th August. I don't know if it ever will be picked up. WORST SERVICE EVER. Same thing happened with my latest order of amount Rs. *** Mode by red tape heels. It was denied pickup because serial number is not matching and i received the product on **th August and on **th August (today) the pickup was cancelled.