Even their tax info. Use the search, not all complaints are linked to the complaints page. Get names of some clients with whom they are working or with whom they have worked. Review the information and talk to those individuals about the agency. Contact adoption support groups in that area and ask about their experience with this agency.
Word of mouth is the best advertisement, positive and negative.
So if you get some odd comments about an adoption worker you may need to look for another worker. Ask for names and info on other agencies and or facilitators that they hire. Do check and background check on them as well. Although your agency may pass all the above checks. Be careful about NEW programs.