A few places should be checked to locate the cause of balance discrepancies.
The Front desk
If the customer has a balance but no outstanding bills, go to the front desk tab and ensure there are no bills for the customer. Bills on the front desk are included in balances and need to be deleted or posted and then paid.
Validate Account
We also recommend using the Validate Account option, which will resolve any issues with the account. This can be found on the Account Overview, under "Options" and "Validate Account".