Will Vodafone replace my faulty iPhone 5s?

So on march 7th 2014 i signed a contract with vodafone for an iPhone 5s. About 7 days later i returned the iphone because it was faulty. The vodafone shop then replaced it with a brand new one. Today 12/05/2014 my phone home button was fine until suddenly it felt like something was stuck in it. I asked a friend to have a look to see what he thinks and he believed that the button is pressed in. At some point the phone sometimes wont wake up until i press it twice. I was wondering if vodafone would replace it again because the phone is faulty. One thing im not happy with is if vodafone replaces it with a refurbished one. I have seriously bad history with refurbished iphones and am very unhappy if vodafone does that because the phone only just went into its 3rd month. Can someone please help me im not sure what to do anymore im getting really sick of this. This is my second phone replacement and it is now faulty again.

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