Paytm — Wrong product delivered to me

Address:	New Delhi, Delhi, 400705
Website:	paytm.com

I ordered iphone 6 -64 GB. However what was delivered was iphone 6 -16 GB. Hence I request return and replacement of order. But when guys from parcel.in came to pick up the order, they could not make a system entry as it was showing return of 64 GB. Hence they did not pick up the order back. Kindly advise who can i return 64 GB phone when I have received 16 GB phone. After this I must have called the customer care more than 10 times but each time they assured pick up within 72 hours and nothing happened. I have also written serveral Emails to them but they only give assurances. Till date neither the product is picked up nor is my money refunded. PLS assist and help me PLS PLS PLS