your best bet is to grab some small metal flat too to try and slide it into the housing where the buttons are. You will then try to pull the buttons back out or see if there is any metal that may be obstructing the button from coming back out. With that model, you should be able to heat the phone using a similar method to the galaxy s5 and separate the display from the frame. This would allow you to get a close up look at the issue. But if you are not well versed in phone repair, this can be a dangerous method of resolution.