Within 10 days after the filing of the list of creditors and the statement of their claims, the assignee shall mail notice of such filing to every creditor who has proved his claim, addressed to the creditor at his usual post-office address, so far as the assignee can ascertain, and shall, within said 10 days, also file with the clerk of the court due proof of the mailing of such notice.
N.J.S. § 2A:19-26