Why isn't my Samsung Galaxy Grand Prime not turning on?

The screen is black and it won't turn on. I try turning it on and holding it for 30 sec and nothing showed. I tryed taking out the battery and putting it the next day but, nothing. Its been in charge at least 2 days and nothing. It was working the other week but now it doesn't. I went to the Metro store where I brought it, they gave me a new battery but, after a few weeks it doesn't work. I never dropped it of anything. It looks brand new. Btw i got this phone like 2 years so far.