My iPhone 4 will not ring,

Hi

I have an issue with my iphone 4. I have had my phone for 1 year and this is its first fault.

It will not ring or alert when a message/ voicemail / email arrives. i have gone through sounds menu and adjusted volume to its full setting.

I have restored my iphone twice and one complete restore as new phone.

i have tried un plug re plg headphones. the weird thing is, is that you can hear all the calls through the earphone but not through the actual built in phone speakers. And it does vibrate!

I am totally lost and am fed up of being shouted at when i dont pick up my phone due to it not ringing.

Please please please help me!

I have tried taking it to the phone shop and all they says is.. well we can send it off but we cant guarantee that there is anything wrong with it!!!!

Regards

N.R