If it appears from the answer of the garnishee that the garnishee was not indebted to the defendant when the writ of garnishment was served, and that the garnishee did not have possession or control of any personal property or effects of the defendant, and if an affidavit controverting the answer of the garnishee is not filed within twenty days of the filing of the answer, as provided in this chapter, the garnishee shall stand discharged without further action by the court or the garnishee and shall have no further liability.