Navision attain aged AR report showing more then i need

Hello,
This is my first post to this site.
I work in collections and have a new boss I am trying to make the aged
A/R report to only show Customer balances where they owe us not ones with a account balance credit due them ( i do not need to see the credit balance due them and it makes the report 100 pages it will cut down the report size by a lot)
anyone help I printed the report using over 45 days usually i do 30 days. as i said i came out over 100 pages
thanks if you can help i would greatly appreciate it