Tracy Bowers thought he knew exactly what he was getting by being a 20-year member of his local YMCA — community, affordable prices and a place where he and his family could focus on their health. So when the Delaware resident shockingly discovered nearly $35,000 in personal training charges years after formally canceling them, he assumed there had been a mistake. How could the globally known non-profit pull a fast one like that ? The dad of two told The Post that he canceled the pricey