Android Questions? Ask Android Device Experts for Answers ASAP
Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
The battery may have suddenly failed completely... but it should turn On still when the charger is hooked up.
This is partly suggested by the fact that the battery was at 30 % when you last used it. Some batteries don't respond well to being partly or mostly discharged a lot.
As for the charger not helping it work, that might be owing to the battery being shorted, or being designed to not work with a defective battery.
Either way, it is out of warranty in all likelihood, but will require a repair tech to analyze the problem and probably to replace the battery (though at this point that is not sure to fix it.)