Seventymm Online Shopping — regarding refund

Address:

Bangalore, Karnataka

on shop.seventymm.com i had buy one bedsheet order no. was-SMA0274988 by the name was pratima srivastava
but the piece was defective so i returned that with courier charges 100/- on 12 august and i checked that it was deliver to its delhi office Branch Office - Delhi
Seventymm® Services Pvt. Ltd.
B-75, 1st Floor
Okhla Phase-II
New Delhi - 110020
Phone:[protected]
Fax:[protected]

at this address and it was deliverd before 24 august as i remember i called up and ask after that i registered complain for refund of my money since that tym and its know 1 month that i did not get any respond from their office or any call and every time i call they use to say that in 2 days they are refunding in 4 days they are refunding but till know 19 sep 2012 i did not got any message regarding my return ..i feel like cheated...
what should i do please help me as i had called and send many mails to them and i doubt that they are cheating me....