The customer authorization (provided in the link you clicked) is out of date, and does not entitle you to use the Blended Threat service.
https://pharmac.govt.nz/news-and-resources/consultations-and-decisions/2022-10-25-proposal-to-widen-access-to-the-meningococcal-b-vaccine-and-secure-supply-of-the-shingles-vaccine