29 CFR § 4000.3 - What methods of filing may I use?
(b) Electronic filings.
(iii) This electronic filing requirement does not apply to information you file to comply with a request we make under § 4007.10(c) of this chapter (dealing with providing record information in connection with a premium compliance review).
(4) When making filings to PBGC under parts 4041A, 4245, and 4281 of this chapter (except for notices of benefit reductions and notices of restoration of benefits under part 4281), you must submit the information required under these parts electronically in accordance with the instructions on the PBGC's Web site, except as otherwise provided by the PBGC.
(c) Information on how to file. Current information on how to file, including permitted filing methods, fax numbers, and mail and e-mail addresses, is -
(1) On our Web site, http://www.pbgc.gov;
(2) In our various printed forms and instructions packages; and
(3) Available by contacting our Customer Service Center at 1200 K Street, NW., Washington, DC, 20005-4026; telephone 1-800-400-7242 (for participants), or 1-800-736-2444 (for practitioners). (TTY/TDD users may call the Federal relay service toll-free at 1-800-877-8339 and ask to be connected to the appropriate number.)