D500 "No Service" Help!!!

Hi I Have Got A Samsung D500 And It Shows "no Service" No Matter Which Sim Card I Put In And It Will Sometimes Pick A Signal Up And I Can Make/recieve Call Etc But Not All Of The Time...the Phone Is Not Barred/blocked As I Have Bought It Brand New Payg Any Help Would Be Appreciated Thanks In Advance..:-? :-?

try epron reset 1st,without sim,if that no fix,check the Power amplifier. measure current that mob get from BATTERY, when pfone is OFF, if its 50 mA or mor - change PA

if it's brand new take it back and get it replaced under warrenty