I had ordered Nokia 503 mobile for my mom. Instead I got Nokia 500 handset. I had to go through a long process of giving back the wrongly delivered handset, get a credit note from them, call those customer care people by giving them the credit note number, authenticate it and then my refund was processed.
Another bad thing is, they don’t credit to any of the bank account. Instead they credit it to paytm wallet and from there only we have to use that money, no other option : -(
My personal advice is not to buy things from paytm.