If you run your battery down to 0% this causes the chip in the battery to "go into a coma" and become unresponsive.
Use the factory charger and cable only. Plug it in and wait. It may take several hours (actually it will take several hours). Just leave it alone. When the chip in the battery "wakes up" the device will boot up and normal charging will resume. If you use the factory charger and the phone does not wake in 12 hours something else is wrong. You can't replace the battery on the 625 without surgery so seek a qualified repair center.
If you find yourself frequently in danger of running the battery flat, invest in a USB power bank. They are getting very inexpensive and are easy to find.