crazy foster parent

How does a foster parent get away with taking matters in her own hand and refuse to give visitation? Let me explain. Last month my Husband and I were matched with a little 2 year old little boy....We had the full disclosure meeting and met the little one along with foster mom and her 20 year old daughter.....Foster mom has had our little one for the past 13 months...he has never had any other foster mom ......Foster mom decided that she wanted to adopt him and some where in the process after having an adoption worker and starting the process she decided to stop and move forward with the adoption.....She stated in the meeting to everyone there that she changed her mind because she did not want the commitment of the next 20 years of raising another child....her children were grown and she did not want to start over......so we moved forward with the process and started the visitation and a few over night visits.Everything went great.....Little boy was developing a connection with us and was doing great during the overnight visits. No crying no asking for foster mom nothing.....just doing wonderful. well after foster mom sees the connection he was developing with us she decided to change her mind again and now wants to adopt him.....even though she was to continue with our visitation she took it upon herself to put an end to them.....she has stopped all communacation and visitation......it has been decided by the social workers supervisior that the adoption with my Husband and I will continue however the social worker is not working with us and allowing her to keep him from us even though we are the ones that are going to be adopting him.....when we last saw our little on we had returned him to foster mom from an overnight visit.....foster mom refused to give us another pickup time or talk to us at all.....and still will not answer the phone or return our texts......so even though we are to adopt him how long can the social worker and foster mom drag this out? When will we get to see him again?