Samsung / Samsung Duos — SERVICE CENTER MAKES MY MOBILE COMPLETELY OFF

Address:

East Singhbhum, Jharkhand

I have samsung Duos mobile which i purchased on 15 aug 2010.from that time its memory card slot hav problem when ever insert memory card ph does not get started or if started it gets restarted again n again the i give it to service center (jamshedpur)on 1st of June 2011 they give it back to me on 15 June memory slot prob gets solved but now my both sim does not response at the same time again I give my cell to service center on 20 June 2011 they return me on 5 July but again it creat problem now automatically mobile get restarted if i talk more then 10 min or i send 4-5 messages it get restarted so i give it to service center on 11 july till 8 aug they dont respose me .I m totally flustered from it plzzzzz solve my problem or replace the set .