Legal help?!

Mariah
My child is 2 years old and never met or seen her biological father I tried to get ahold of him when she was 4 months old after he got arrested for putting his hand on me but his mom interfered and told me to leave her family alone and that my child was forgotten and replaced so I left them alone, she has a daddy now my boyfriend she knew him since she was 4 months old he helped me raise her and that's who she calls daddy. Well when I just had her my mom wanted me to put him on child support the biological father I didn't want to but since I was in her house at the time I felt like I had no choice they barely got back to me about child support this year I been trying to cancel it for some time now but they won't let me since she is on Medicaid and I been waiting for my insurance to kick in from my job so I can cancel it. Today some lady from the attorney office called and told me the date to attend the hearing and wanted me to bring my child to do a DNA test as requested from the sperm donor and I don't want to go threw with it him and his family are toxic people she has a dad and grandparents who love her they were fine with him putting his hands on me while I pregnant and still stood by his side. If I try and cancel it again will they let me since he wants a DNA test to be done? Or would I have to go threw with it? I'm so stressed out about it because I didn't want her to know them people she is such a happy baby his family have no morals and refuse to accept responsibility for their actions I'll be scared to leave my child with them.