We stress that if the service is done by registered mail, proof of service shall consist of the affidavi​t of the person effecting the mailing and the registry receip​t, both of which must be appended to the paper being served. Absent one or the other, or worse both, there is no proof of service. In Valley Golf and Country Club, Inc. v. Dr. Reyes, we emphasized that registry receip​t per se does not constitute proof of receipt. (Mariano vs. G.V Florida Transport, G.R. No. 240882, September 16, 2020)