(a) Service of a NOVA (§ 904.101), NOPS (§ 904.302), NIDP (§ 904.303), Notice of Proposed Forfeiture (§ 904.504), Notice of Seizure (§ 904.501), Notice of Summary Sale (§ 904.505) or Written Warning (§ 904.402) may be made by certified mail (return receipt requested), facsimile, electronic transmission, or third party commercial carrier to an addressee's last known address or by personal delivery. Service of a notice under this subpart will be considered effective upon receipt.

(b) Service of documents and papers, other than such Notices as described in paragraph (a) of this section, may be made by first class mail (postage prepaid), facsimile, electronic transmission, or third party commercial carrier, to an addressee's last known address or by personal delivery. Service of documents and papers will be considered effective upon the date of postmark (or as otherwise shown for government-franked mail), facsimile transmission, delivery to third party commercial carrier, electronic transmission or upon personal delivery.

(c) Whenever this part requires service of a NOVA, NOPS, NIDP, document, or other paper, such service may effectively be made on the agent for service of process, on the attorney for the person to be served, or other representative. Refusal by the person to be served (including an agent, attorney, or representative) of service of a document or other paper will be considered effective service of the document or other paper as of the date of such refusal. In cases where certified notification is returned unclaimed, service will be considered effective if the U.S. Postal Service provides an affidavit stating that the party was receiving mail at the same address during the period when certified service was attempted.

(d) Any documents or pleadings filed or served must be signed: