Where property of the defendant has been attached and an affidavit has been filed by the defendant, the Superior Court or the Court of Common Pleas or the justice of the peace (as the case may be), shall proceed to direct an issue to be tried by a jury at the bar of the Superior Court or by a reference to 3 judicious and impartial citizens before the Court of Common Pleas to be appointed by the Court or before the justice of the peace to be appointed by the justice of the peace (as the case may be) for ascertaining whether there is a just demand and the amount thereof, and their verdict or finding shall be final and conclusive.