It will not be considered served and they are clearly avoiding service. You need to hire a process server to personally serve them. If they continue to evade service, you may be able to use that letter, in their handwriting, along with other evidence of evading service, to ask for sanctions. If the item you are servicing is a summons and/or complaint, those need to be personally served anyway so there would be no real harm.
The answer will depend upon what "papers" you are trying to have served. For example, a summons cannot be served by mail. A subpoena cannot be served by mail.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.
I agree with Mr. Chen. It depends on what you are trying to serve. If the party has appeared in the action and the package was addressed to that party at their service address -- they were served so long as you were not a party signing the proof of service. However, such "service" would be improper for a summons or subpoena.
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