Section 13: Restriction on conveyance of letters except by post.

(1) No letter, unless exempted by law, shall be conveyed into or out of Nigeria, from or to any place between which the Postal Service is established, or to be delivered or be distributed in Nigeria, otherwise than by or through the post.
(2) A person who contravenes the provisions of subsection (1) of this section, commits an offence under this Act and is liable on conviction-
(a) in the case of an individual, to a fine of not less than N5,000;
(b) in the case of a body corporate, to a fine of not less than N20,000.