Birth Certificate Problem

Good Morning. I hope may makatulong sakin dito on what to do. This is about my son's birth certificate. So before ako manganak nagkasundo kami ng father niya na our son will have his last name since hindi nman po kmi kasal. But, na tag as late registered po kasi wala nman sya noong nanganak ako. Pero hindi po namin natapos eh file ang birth cert ni baby sa munisipyo kasi biglang di ko na sya macontact and hindi daw pwede eh process kapag wala both parents para pumirma.
So I'm planning na ibalik na lng sa apelyido ko yung bata.
But I don't know how and not really sure sa desisyon ko kasi magiging iligitimate yung anak ko. I'm really hoping na may makatulong sakin. Salamat po.

your son is really illegit because you are not married. ask that the old application be voided so you can file a new one