Hi @asomething
After months of not being charged the battery may have become depleted beyond recovery.
Try charging the battery for at least 3-4 hours and check if this "kick starts" it back into life again.
If it does allow it to fully charge before use.
If still no good the battery will need to be replaced.
Here's the ifixit [guide|146399] guide that will help.
Replacement batteries are available online. Just search for [https://www.google.com/search?client=firefox-b-d&q=EB-BR880ABY|EB-BR880ABY] to find suppliers (examples only) that suit you best.