Can NEVER get ahold of the CPS worker?

OK, I try and try to get ahold of the CPS worker in charge of the my children's case but she never returns my calls. I do not think that I am being pesty. I only leave one message a week, for the last 3 weeks. My almost 4 yo fs is telling us stuff about things that he has seen regarding his bio and men and stories of being left all alone and her locking him outside, etc, etc. I feel that the worker needs to know these things. I am journaling them all of course. This is our first placement and I guess that I am a bit niave about how the system works. Bio is working the plan right now, even though she has lost 8 other children in another state they are talking her up like she is the queen mother. I don't get it. I guess my question is, do they (CPS & court) take things that children say into account before they return children to the bios? My fs is way to "educated" about things at his young age and I am worried about this poor guy, as well as his 1 year old brother and sister. Wow, the life of a foster parent is certainly - uncertain. You go from court date to court date, from story to story, from worry to worry. Sorry to ramble but I'm curious to hear from you veterans out there. Thanks.