Samsung Sgh J700 — not returning mobile after repairing

i had purchased my mobilesgh-j700 in august 2008. after that in june 2009 my mobile charging jack was not working properly.so i submitted my mobile to a samsung service center (rahul traders) fountain chowk rani bagh delhi. i had submitted mu mobile on 19 june 2009. but now more than one month has passed. they are not returning mobile.i have gone to the center various times but they just say that "after one week". i am fed up with samsung services.i had also asked them to give my mobile unrepaired, but they dont listen.

if someone goes with his her mobile in the period after gaurntee then the just return mobile with in one day. it means they just need money for every task. they dont want to repair the mobile in guarntee period.

please help me and tell what should i do.