Can you be over drawn from savings account?

I had a checking and savings account with a bank. When I moved to a different town I closed my checking and just left my savings, the town didn't have my old bank locally, and I didn't want to drive an hour just to do my banking. I took everything out of savings except for $1. Well years later I come to find out that supposedly I have over drawn in my savings account.... I am very confused on this, because I don't have a debit card or any payments that would have had the savings account. The only way I could have deposited or withdrew and money from the account was with my little black book, I had to take it inside and the tellers wrote in what my deposit or with drawls are. I am confused as to why I would have over drafted by $50 for a account no one had and I never used. The bank isn't giving me any information other than it was charged off last year ???? whatever that means. So I'm very lost and confused and extremely upset. Can anyone explain this to me better?