Credits and payments will only auto apply to charges assigned to the Payer listed on the Payers tab of the record.

To manually apply the payment to a charge:
  1. Open the Payment and select the Student Billing Detail tab
  2. Click Add/Edit Applications
  3. Click  Other Record's Charges or Advance Deposits
  4. Search for record that the charge is assigned to and click Open
  5. Click the Apply? checkbox next to the charge to apply
  6. Click Save Applications
  7. Click Save and Close