Why wont it turn on (BLU Life X3)

My phone a BLU life X3 just stopped working, what I mean is that it just stopped turning on even though it worked about a half an hour ago. My phone isn't warranted and I don' have the key to take the memory out and I don't know how to take off the back and I don't want to do a factory reset what should I do? should I get another one and use the key or should I just try to take out the back? This is what I think is closest to my model