Snapdeal Online Shopping - Snapdeal not ready to pickup and replace

I had ordered shoes on *th Oct **** bearing order no. *********** which was delivered on **th Oct **** for which on the same day I had requested for a replacement due to issue in size. Ref no ********. Thereafter I am receiving messages from snapdeal and their courier partner Ecom Express that the parcel will be picked up. Finally today **th Oct **** I have received message that your Pick is failed to say that our courier person tried to contact you but you are not responding. Yes, I had received a call from Ecom Express on **th & **th Oct **** but when I pick up the call it gets disconnected. I have also tried calling snap deal several times but it was of no use and I could not connect to the customer care executive. In the evening, I have mailed and chatted with Snapdeal and they promised me that package will be picked up soon but it was not fulfilled to date.