For an injury or illness to be duly compensated under the terms of the Philippine Overseas Employment Administration-Standard Employment Contract (POEA-SEC), there must be a showing that the injury or illness and the ensuing disability occurred during the effectivity of the employment contract. Additionally, Section 20(B) of the POEA-SEC, paragraph (3) requires:   xxxx   3. upon sign off from the vessel for medical treatment, the seafarer is entitled to sickness allowance equivalent to his basic wage until he is declared fit to work or the degree of permanent disability has been assessed by the companydesignated physician but in no case shall this period exceed one-hundred twenty (120) days.   For this purpose, the seafarer shall submit himself to a post-employment medical examination by a company-designated physician within three working days upon his return except when he is physically incapacitated to do so, in which case a written notice to the agency within the same period is deemed as compliance. Failure of the seafarer to comply with the mandatory reporting requirement shall result in his forfeiture of the right to claim the above benefits. (emphasis and underscoring supplied)     Respondent was thus required to undergo post-employment medical examination by a company-designated physician within three working days from arrival. He failed to comply with the requirement, however, without explanation or justification therefor. Hence, he forfeited his right to claim disability benefits.   Respondent’s claim of having reported to petitioner Transmarine’s office within three days from his arrival in the Philippines remains just that. As duly observed by the NLRC, respondent merely consulted a private practitioner more than one month after his arrival – three weeks after he had already filed his