High battery usage is not an indication of a hacker. Go into your settings, then the battery section. Tap the 3-dot menu in the top right and select the item that comes up - battery usage. This will show you what is using battery.
If you need additional help or have more questions or details to share, please join the site so you can reply in this thread. See this link for instructions on how to join Android Central.
Welcome to Android Central! I agree with hallux -- there are so many reasons that are much more likely than being hacked, so no need to jump to that very unlikely conclusion.
Charge up to 100%, then let it drain to 20-30% with normal usage, without charging in between. Then show us:
1. The main Settings>Battery screen.
2. The fullscreen battery graph screen (which may show Awake time and Cell Signal Strength).
3. The Screen category (to see total Screen On time).
4. The Cell Standby category, if present (to see Time Without Signal).