My iphone4s keeps freezing and turning off

Question

I received an Iphone4s for christmas & it was perfect. Then however after about after 4 months the wifi stopped working, so I had to send the phone back to Apple and pay €40 for a new phone (even though My phone at the time was insured). Now this new phone, after 4 months of having it keeps freezing (maybe 7-8 times a day) and turning off & its infuruating because I cant really do anything with it. After a week of having the phone i tried to take a picture with the camera turned to face me and the phone just froze and i couldnt use the camera, it happens everytime i try to do it. I didnt mind too much because i could do without that but this is really annoying now because the phone is new and i take great care of it!
I have reset the phone, restored it etc and dont know what else to do

Answer 1

I am having the same issue.  ** MY IPHONE IS TURNING OFF RANDOMLY ** and it's driving me crazy.  
THE SYMPTOM... I am using my phone fine and then when I go to send a text, take a photo, etc, it just turns off. 
This started a few weeks ago after upgrading to the new IOS.  The 'symptoms' increased in frequency and my phone started turning off more frequently.   I took my Iphone to the apple store. They reset the phone to factory standards and the problem still exists. 
THE PROBLEM: The guy at the Genius Bar said he knows there is a known software issue, and this looks like it's affected my processor.  BUT this was only after I told him that I have been reading about a lot of other people having the same problem. 
THE SOLUTION:  Are you having the same issue ... Reply to this post and let me know.   If a lot of people are having the same problem, Apple will probably just swap out the phones.