27 C.F.R. § 70.27
(2) Elements of institution of a proceeding to quash. In order to institute a proceeding to quash a summons, the notified person (or the notified person's agent, nominee, or other person acting under the direction or control of the notified person) must, not later than the 20th day following the day the notice of the summons was served on or mailed to such notified person:
(iii) Notify the recordkeeper by sending to that recordkeeper by registered or certified mail a copy of the petition.
Failure to give timely notice to either the summoned party or the Bureau in the manner described in this paragraph means that the notified person has failed to institute a proceeding to quash and the district court has no jurisdiction to hear the proceeding. Thus, for example, if the notified person mails a copy of the petition to the summoned person but not to the designated Bureau employee and office, the notified person has failed to institute a proceeding to quash. Similarly, if the notified person mails a copy of such petition to the summoned person, but instead of sending a copy of the petition by registered or certified mail to the designated employee and office, the notified person gives the designated employee and office the petition by some other means, the notified person has failed to institute a proceeding to quash.
(c) Presumption no notice has been mailed. Title 26 U.S.C. 7609(b)(2)(B) permits a notified person to institute a proceeding to quash by filing a petition in district court and notifying both the Bureau and the summoned person. Unless the notified person has notified both the Bureau and the summoned person in the appropriate manner, the notified person has failed to institute a proceeding to quash. If the copy of the petition has not been delivered to the summoned person or the person and office designated to receive the notice on behalf of the Bureau within 3 days from the close of the 20-day period allowed to institute a proceeding to quash, it is presumed that the notification has not been timely mailed.
(26 U.S.C. 7609)
[T.D. ATF-301, 55 FR 47609, Nov. 14, 1990]