this is one of those yes but answers...
if paternity has been established, then you have equal rights to the child as the mother does. (if custody has not yet been established)
you could go to the school and pick the child up and attempt to keep her. the mother could do the same to you and you could both play this awful games with the child. but in the end who are you hurting? the child.
this probably isn't the answer that you want to hear. but it would be better if you took the high road on this one.
keep trying to call your daughter and to visit with you daughter. keep a journal of every attempt to talk with you daughter or to see your daughter and everytime that you were refused. send her emails stating the date and time that you want to see her, see if she will email you back. get solid evidence that she is denying you contact with your daughter.
you then take that information into the mediation with you. you let the mediator know that you have not seen your child since XX-XX-XXXX date. that the mother is denying contact and visitation and these are emails, logged dates and times, etc. to prove that she is doing so.
the biggest job of the CP is to help the NCP maintain a close relationship with the child. they are suppose to encourage visitations and to be very flexible on the scheduling to do so. she is already showing how she will act as the CP and it will not cast a good light on her.
just don't give up on the attempts. try to be as involved as ever. be able to show the mediator that you are a very active father and you want to remain that way.