I got "No service" in my Iphone 4S after update to IOS7.1

I'm having the same issue on my iphone 4S since upgrading to IOS 7.1, and it's not just me, I've found a lot of people on the Internet with the same problem.

At first I thought is was a carrier problem and I even changed my Sim card for a new one, but it didn't solve the problem.

Then I put my sim card in another phone and it worked just fine, so I tried:

Reset network settings,

Reset all settings,

Restore my phone with the previous backup,

Restore my phone as new

And any of these worked for me. After almost losing hope I turned off my 3g connection and the signal came back, even when I was using wi-fi. Also the battery life is a million times better.

So I called apple support and they told me that it seams to be a hardware malfunction and because my guarantee is expired I have to pay to get it changed for a new one.

I think they don't know what they are doing and don't know how to fix it so it's easier to blame the hardware and charge us for they mistakes.

I'm still waiting for some update to solve my problem because before the update 7.1 I had a perfect functional phone.