Well since you never paid for it, they will probably hold the units from you, or if you are planning to go back to that same school, not allow you to graduate untill you pay them. If you want credit for any of those classes,you would list that school. There is something called academic renewal/forgiveness that you might want to look into, it will erase the bad grades from your past if you show improvement and maturity when you go back. Check to see if the school offers that.