Samsung Mobile — unlock phone is not covered under warranty

i purchased samsung mobile on 15 Nov 08 for vergine mobile but,
it is unlock phone having 3rd party s/w installed in it. Before two days the screen of mobile is get totally blank, phone is working but the screen appears only white. When asked in to samsung service center at ghatkopar, they told it is tampered case and wl not be covered under warranty. When contacted to shop at vashi from where i purchased phone. he is ready to repaire the phone. But i want to complaint about shop keeper as he cheeted me, by telling that phone is under warranty.
pls tell how long i have to wait to get solve my problem.
also tell whole procedure.
Thanks, Sandeep Deokar [protected]