The appeal or petition from a determination, redetermination, order and notice of assessment, appeals decision, or commissioner's decision is deemed filed and received if properly addressed and with sufficient postage:
(1) If transmitted through the United States mail, on the date shown by the United States postal service cancellation mark;(2) If mailed but not received by the addressee, or where received and the United States postal service cancellation mark is illegible, erroneous, or omitted, on the date it was mailed, if the sender establishes by competent evidence that the appeal or petition was deposited in the United States mail on or before the date due for filing; or(3) In the case of a metered cancellation mark by the sender and a United States postal service cancellation mark on the same envelope or other wrapper, the latter shall control.2017 3rd sp.s. c 5§ 35. Formerly RCW 50A.04.515.