"I need to turn it on to test functionality and delete info off the memory card I need to turn it on to test functionality and delete info off the memory card". First suggestion. Remove the memory card and keep it.
Suggest you leave the battery in a charger for an extended period of time to see if it can be recovered. I have batteries that are 20 years old that work perfectly, but some will go into a deep discharge.
Frankly, I would hazard that the EOS M is not going to get you enough money to pay for a new battery as a viable economic solution. I have one, it works perfectly and it's not worth selling, I use it for some specific types of photography instead.
cheers, TREVOR
The mark of good photographer is less what they hold in their hand, it's more what they hold in their head;
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris
