To apply billing to a family account when the plan has ended: 
1. Go to the family's main landing page 
2. Hover over the blue tab on the left side
3. Go to More Options > Apply Fees & Discounts
4. Select the desired Fee or Discount from the billing item filter
5. Choose applicable fee/discount from the list in left column
6. Drag fee/discount from left column into right column
7. A box will then pop up where you will enter billing amount, reason for adjustment, and month to be applied (adjustment will always be placed in last month of payment plan)
8. Click Save