defendants on or before November 3, 1965, the date when the order in the envelope was returned to the Urdaneta Post Office. This finding of the court a quo is untenable.   In Barrameda vs. Castillo, this Court held:   Therefore, to obviate injustice, it is incumbent upon a party, who relies on constructive service or who contends that his adversary was served with a copy of a final order or judgment upon the expiration of five days from the first notice of registered mail sent by the postmaster to prove that the first notice was sent and delivered to the addressee. A certification from the postmaster would be the best evidence of that fact (Grafil vs. Feliciano, L-27156, June 30, 1967, 20 SCRA 616). The mailman’s testimony may also be adduced to prove that fact, as was done in Aldecoa vs. Hon. Arellano and Siguenza, 113 Phil. 75, 78.   The postmaster’s certification as to the sending of the first notice ‘should include the data not only as to whether or not the corresponding notices were issued or sent but also as to how, when and to whom the delivery thereof was made.’(Hernandez vs. Navarro, L-28296, November 24, 1972, 48 SCRA 44, 64, per Barredo, J.).   As stressed by Justice Barredo in a recent case, ‘there must be clear proof of compliance with the postal regulations governing the sending and receipt of the notice referred to in’ section 8 of Rule 13 (Vecino vs. Court of Appeals, L-38612, March 29, 1977). The mere exhibition in court of the envelope containing the unclaimed mail is not sufficient proof that a first notice was sent.   Note that in a certain case a first notice was sent but it was received by the addressee’s eleven-year old child who did not deliver it to the addressee himself. It was held that to apply the presumption in that case and to insist on constructive service would work an injustice rather than promote justice (Cabuang vs. Hon. Bello, 105 Phil. 1135, 1138).   In the instant case, there is no evidence that the first notice was sent to Barrameda’s lawyer and that it was delivered to him or should have been received by him. The envelope containing the unclaimed mail was presented in court. The face of the envelope contains the notation ‘Returned to sender. Reason: Unclaimed’. Above the stamp, on the back of the envelope, with the legend ‘City of San Pablo, Philippines, Jan. 29, 1966’, are written the dates, ‘2-3-66 and 2-9-66’. Written also on the back of the envelope are the following: ‘R to S, notified 3/3/66’.   Relying on those notations on the envelope, the trial court literally and rigidly applied the presumption as to constructive service. It