IPhone 4s Problem. Will Apple Replace It?

Had my iPhone 4s for 6months + Its played up a fair bit during this time but it's recently got absolutely unworkable.
It won't send messages unless it wants to, won't receive messages, the touch screen won't let me accept or decline calls. Someone can be stood next to me ringing me and myphone won't ring. Messages often come through blank.

We've thought it might of been my boyfriends phone so we had it sent off for repair and called the message centre and they said they was nothing wrong with his phone.

As its on a 24 month contract I can't be dealing with this phone going wrong every day. Will Apple replace the phone?

Added (1). Yes bought it brand new 6 months ago. I didn't take it in before because it would only do it once in a blue moon now its every single day atleast 5 times doing all the problems or the same one.

It should still be covered under the 1 year

If its not second hand and it's under 1 year old then apple should

Take it back to the shop you got it from then you will find out if they will tell you if they will repace it or not. They should depending on where you got if from.

It's still under warranty. They'll repair or replace it. Why haven't you taken it in before now?