When a garnishee is a financial institution and fails or refuses to file a garnishee answer by the fifteenth day after the date of service of the summons of garnishment, such garnishee shall automatically be in default. The default may be opened as a matter of right by the filing of a garnishee answer within 15 days of the day of default and payment of costs. If the case is still in default after the expiration of the period of 15 days, judgment by default may be entered at any time thereafter against such garnishee for the amount remaining due on the judgment obtained against the defendant as shown in the plaintiff's affidavit of garnishment.
OCGA § 18-4-22