mother not present/father wishes to acknowlege yet civil reg is not helpful

i need to sign/acknowledge a childs BC.
i tried to go to the hospital(actually they refused to help me) then when i had the "info" (vaild id) by that time it was already forwarded to the Civil reg,
the mother is not in the country i have the child w/me.
what recourse do i have to get the "acknowledgement " process started so that this child will be acknowledged
yes i know ASUF needs to be sign but what if the mother is not present? the civil reg has said this, then said that , and its not clear,
any suggestions is appreciated

can't do it without the mom

thank you. i have tried to contact the mother yet ... no success
would a affidavit from the barangay stating that i am supporting the child
and mothers where abouts are unknown?

What if the child is of legal age? I am 21 years old already now and was born before my parents wedding. I have no Surname on my Birth Certificate, only my name and my middle name-which is my mothers maiden name.. The documents I had only is affidavit of acknowledgement signed by both of my parents and the affidavit for the delayed registration of birth. All my records in school , I used my fathers surname. I have started to encounter problems when I was getting a passport. My mother abandoned us and I don't know where in the world is she now. I really need your legal advice what to do. I am not really after legitimacy. I just need my fathers surname on my birth without needing the appearance of my mother. I've read about the AUSF and the Affidavit of Paternity, could it be the other way around just to have his surname on my birth certificate? I am aware that I have the right to file it myself and my father is even very very willing to sign all those documents mentioned. Please help us what to do. This means so much to me more than anything. Thank you so much!