What does HOA do about delinquent homeowner falling further behind?

We have a delinquent homeowner has no job getting farther behind. What are options in North Carolina?  We have followed all rules about warning, late charges, interest charges, etc. She has promised regular small payments, but has not made them. We know she hasn't much money, but she doesn't pay small amounts from what she has. We have told her we will file a lien, but haven't. What are the legal ramifications for that?