If a garnishee, personally summoned, shall fail to answer as required by law, or if a scire facias on a judgment nisi be executed on him, and he fail to show cause for vacating it, the court shall enter a judgment against him for the amount of plaintiff's demand; and execution shall issue thereon, provided, however, that the garnishee may suspend the execution by filing a sworn declaration in said court showing the property and effects in his possession belonging to the debtor, and his indebtedness to the debtor, if any, or showing that there be none, if that be true; and by such act and upon a hearing thereon, the garnishee shall limit his liability to the extent of such property and effects in his hands, and such indebtedness due by him to the debtor, plus court costs and reasonable attorney's fees of the judgment creditor in said garnishment action.