Samsung India Electronics Pvt Ltd — Defective phone

Address:

South Delhi, Delhi

Hi,
I purchased 'Samsung Galaxy Grand Duos-I9082, just 4 days back dated 13/7/2013".
I am not able to change the ringtone or message tone as I am getting error popup message -
" Unfortunetly, setting getting stopped" or "Unfortunetly, Messaging getting stopped " and going back to previous screen.

Please find the attached bill as it just four days of purchase. Its really shameful for leading mobile brand like Samsung to deliver this kind of defective product to its customer.