Paytm Mobile Solutions — first product one size bigger and after replacement received wrong product

This is to inform you that my order no- [protected] was first delivered one size bigger and after replacement seller shipped wrong product.It took 15 days in this process and still haven't received the right product.Now after calling customer care she said the amount will be refunded.First thing is if seller has shipped the wrong product then i have the right to receive the right product .The customer care agent just hang up the call.Is this how you treat your customers?
Second thing is even if i want to process a refund the amount shows as zero.I want a reply ASAP.
If i had to waste soo many days i would have rather ordered from Flipkart.Atleast would have got better customer care responses