Housefull International Furniture — Selling products which are already out of stock

Address:	Mumbai City, Maharashtra, 400067
Website:	www.housefull.com

Order id - hfod01155 was placed on 18th june 2016 with estimated delivery date - 29th june 2016.
However delivery was delayed to 8th july 2016 without any intimation.
Further when i called up their customer care number i was informed that the product was out of stock from the beginning.

How can they sell an out of stock product?
Also if it was out of stock from the beginning it should be their duty to inform about the same.
I only came to know about it on 6th july 2016 when i called up again to know the status about it.

I should be compensated for it