I have a friend that has endless problems with his ex girlfriend as she refuse him to see his chold or have any contact,he pays his maintenance but still not allowed to see his son, she will tell him to come visit but when he get's there she isn't at home,she will ask him for airtime so that she can send him photo's of his 7mnth old son,she will send one picture then nothing after that always playing mind games with him,please any advise will do.

He should go to court and get an order for visitation. A child has the right to know both parents, and she has no right to stop him seeing his daughter. It sounds like he might be in a position to sue for joint custody, which usually works out as weekdays with the mother and weekends and holidays with the father, but he should certainly get some clear visiting times.

Is there a court ordered visitation schedule? If not then he needs to get one. If there is ten he needs to get the court to enforce it.

First it is normally called child support, and should be court ordered,
He has all the rights that the court gave him in the child custody and visitation agreement