How do we go about getting our grandchildren back after a minor offence with CPS.

*My sister lost custody of her children and my parent's were awarded temp custody Nov 2013. *My mother has a 20 y/o child abuse case (unfounded) based on my sister (Mother of kids).. she kicked my pregnant mother in the stomach and my mother defended herself.) *4 months ago, my mother was having copd issues and we went to store to pick up her meds. While leaving the 3 children in the hoem alone for around 45 minutes. *CPS shows up in the window and takes them b/c they were home alone. *They told us we could not have them back b/c my mother had the 20 y/o case which the judges knew about before granting temp custody. *CPS told us to file appeal, we did. The appeals found the cases against my mother to be unfounded. They referred us back to cps case manager and supervisor. *CPS has been giving us the run around and claims to not know exactly what the process is in regard to getting the kids back. *We cant get in touch with anyone. Decided to ask lawyer for advice.