How long should a factory reset take? I did a factory reset on my LG Optimus L70, and it showed a screen that said "Erasing..."

Shortly after, it showed the MetroPCS splash screen, and it's been stuck on this screen for over 2 hours. How long should a factory reset take?
Factory reset has already been done. Now you need to take the battery of or reset the phone again. Thats the only way that its gonna work.