for clarification --- 2 years na nilang wini-withheld ang custody ng anak mo? 2 years ago na ba nila dinemand na you have to pay for all the things that they spent on you and your kid? if 2 years na --- mas malaki yung possibility that they are after to 'own' your child, and not give to you na.
better ask the help from the barangay, but better first, seek help from the PAO or the women's desk sa police station. mahirap din to talk to the barangay to fix a 'settlement' (wherein you pay and write the terms of payment, including the custody of your child), tapos you haven't consulted a lawyer. women's desk has a woman policeman, but she's not a lawyer. for something so sensitive, seek the advise of a professional, who could look at documents and give you an honest and professional opinion.
that being said, gather your evidence. yung birth certificate ng bata, tapos have you had medical proof of all the physical harm that you got from your uncle and his wife? not that you will raise these, pero for your protection, you should have evidence also, just in case, their money and influence could buy them their freedom.
if you live in a different barangay, complain where you live, para they will have to go there, and for you to get a 'neutral' place to hear your complaint, kapag sa kanila, biased yung barangay officials. whatever they say, you have absolute and exclusive right over your child ---- just don't sign adoption papers, or other statements that would 'give' them custody.
but, before you do that, be financially ready. where will you put your child once you get her/him? who will look after her/him when you work? these are the things that you have to make provisions for as well. where will you live? hopefully, you have a willing friend/relative that could help you as well.