Hello Humdefense,
I'm thinking that you have your invoice showing the account balance in it. Let me show you where you can change that.
- Click on the Gear
- Select Custom Form Styles
- Hit Edit next to the style you're using
- At the top click on Content
- Remove the check next to Show on invoice
- Done
That should show you just the amount due on that particular invoice. Let me know how that goes.