Samsung — I need immediate replacement.

Dear sir,
I brought neo plus, imei-*358313/06/558221/0*imei-338312/06/558221/2, on 26/6/15, from s.S.Technology, siliguri, phon-[protected]/[protected].Cash memo no.3289, vat no.[protected].
The set is found faulty, on complaint, saler said, to upgrade software.They upgraded, now the set is not working at all.On replacement demand, they insist to purchase a new set again.
As a samsung mobile user, i know, if the set has major problem within 7 days..Replacement is assured by samsung, which i availed in my earlier case(Star advance ).
So, please help me by replacement.
Yours urgent reply solicited, to avoid consumer court harrasmet.
Thanking you,
Bhaskar mozumdar
[protected]/[protected]
[protected]@gmail.com
Siliguri, darjeeling, 734401, west bangal.