You may have a dead battery or the charger isn't working. The other day I went to charge my phone and plugged the charger into a power strip , when I went to use the phone it wouldn't turn on and after looking at the phone , the charger and the power strip I found that the power strip was not turned on so the phone didn't charge.
You may want to do the same and make sure that the wall outlet is working and even try a different outlet or maybe the wall plug is on a switch ?