It's possible that Genie may not have had a chance to catch up with the changes you've made in an Account History, which can result in an incorrect Account Balance showing. To correct this, simply open the patient's Demographics and select the Account Holder box.
This will open the Account Holder record. Simply select Update Balance and this should force Genie to pull in the correct outstanding balance for the Account Holder.
If the balance is still incorrect, we would recommend running a Check Integrity.