Problem with my samsung SGH-j600 phone

Question

I have bought the phone (samsung j600)just a few days ago and have found out that after every 12 to 13 hours i can't call anybody from my phone also i don't receive any calls ,when anybody calls my phone they get a reply that the phone is out of coverage area or is switched off ,also i cannot receive and send messages at that time . However once i switch off and switch on the phone again the above problem is solved and i start receiving calls& messages.this is happening everytime.please guide me as to what can be done

Ya. I have the same problem. please hel[ me out