cps custody

just a few days ago I received a letter from department of family protective services about a hearing that was held for a child and the parent child relationship between the mother and her has been terminated. It says I have 90 days to file a suit to modify the courts order and manage custody of the child. The notice was required by cps handbook 5561.3
notice of termination required for relatives and Texas code 161.2081.

It then states any further questions to contact the supervisor or the case worker. It only had contact information of the case worker.

when I received the letter, I made contact with my family to find information about who this child was because I did not recognize the child or the mother involved, other than that the child had the same name as my grandma. I found out that my 81-year-old grandma knew about it the entire time but never told the rest of the family. She has been unreasonable and grieving over the loss of my dad just last year and apparently this came up right around the time that my dad died. My dad had been married and this was not his wife. When I asked my grandma, she told me that the mother of this child is a drug addict and a prostitute, and she lied about having my dad's baby for money. I dont know how much of that is true, that is just what she said and if she is my biological sister then it really doesnt matter. All the more reason to show her all the love she can get from her family.

the rest of the family and I know my grandma is emotional and unstable, and we believe there is truth that this could be my dad's daughter.

The entire family was shocked and none of us had any clue. I was not the only one to receive this letter. my brother, sister-in-law and aunt all received this letter for the very first time. None of us had any knowledge prior to this letter. We decided that we needed to get my sister and bring her home where she belongs. We know that we can provide for her and show her love and she will be with her big happy biological family.
I called the case worker provided on the letter and explained to her we had no idea we had a blood relative and that I would like to care for my sister. She told me that in a couple days she was about to hand over the case to a adoption worker and her foster family wants her. she also told me that i am suspicious because i should have received a letter a year ago, she said she talked to my grandma over the phone and my grandma told her no one would want her and was uncooperative. she said she sent out letters to the family and my dad's friends in Texas.
My dad moved to Texas for his wife, I do not know any of my dad's new friends in Texas. Also, besides my 81-year-old grandma who did not share with the rest of the family, none of the rest of us received any knowledge whatsoever over the matter. My dad's wife had no idea, my step siblings had no idea and none of my biological siblings had any knowledge. not to mention my dad's siblings as well.

She then made these promises to me. Had me send paystubs, pictures of my ID, and told me she was submitting a home study for me this week. She also told me she would send me pictures of my sister.
I repeatedly asked for a DNA test, and she kept telling me she had a meeting regarding my sister and would give me more information after the meeting.
when she did not contact me the day of the meeting i reached out to her and she said she doesn't want to say anything wrong, so she needs to have virtual meetings with me and her supervisor. when I asked for a schedule, she said she is very busy and will talk to her to get a schedule time and date hopefully for next week and let me know when that is by the end of the week. I asked about the DNA test again and she said I have to talk to the supervisor about that at our meeting. I asked for the picture of my sister, and she said she was driving but will send me a picture this week of my sister. Friday comes and i message her again for an update and a picture. later that day she calls me and tells me I keep asking for pictures all week and she cannot give me that. also, she is no longer on the case and i have to speak to the adoption worker. she also said that my sister's lawyers are still deciding if i can have the DNA test.
I asked her who I contact for an update, and she said the adoption worker. I asked for the supervisor's number, the adoption workers name and number and contact for the lawyers. she said everyone is too busy and i can only talk to the adoption worker and she's too busy to give me that information right now.
I'm trying to contact a lawyer and get help. I feel devastated right now. this baby has to be with her biological family, never question if we wanted her because I do, and I'm prepared and able. I don't know what to do or if I even have a chance of getting her. please share advice.