I agree with those JM who consistently told you it's the airline that forbid you from boarding. If I were you, in parallel, I would anyway book an online appointment asap, then perhaps you don't need to wait at 6am for same day service. So that there's slight chance to get a new one before your boarding.
My experience was I submit online application via gov.hk website. I just took a latest photo at home, then submitted together with HKID and passport. 2 days later, an email already informed me to collect passport in 15 calendar days.