Nokia — FAULY HANDSET

i have purchased Nokia 5610 mobile on 16/03/2008(sunday) from Hotspot Mobile Store (Phase 3B2, Mohali, Punjab) in the evening. and when i started using mobile i found that mobile is restarting ocassionaly when making a call after 5-10 min. then next day evening(within 24 hrs) i went to the store and told them about this problem. then they reset my phone and said the problem will be solved and told me that if this problem persist then i should go to Nokia Care. they said that they have no responsibility on their part.

then i went to Nokia Care (Phase 7, Mohali, Punjab) on 17/03/08, they said that there may be some virus in the software and they replaced the software(free of cost), but the same problem persisted. nxt day(18/03/08) i again went to Nokia care, they again re-installed the software, but the same problem remained. then next day(19/03/08) i again wnt to Nokia Care then they said u have to keep this mobile with us for atleast 15 days so that they can get it repaired by the company.
now i just want the store to replace my faulty Mobile set, but they are saying that they have no liability to replace the mobile, its the responsibility of Nokia care.
u help me out and guide me, since i m a office going so i don't find much to address such issues & to go to Nokia care and Hotspot Mobile Store daily. on thing more, i want to ask can i move to consumer forum to address this issue.