The mother of my child is causing my child mental distress and making him say things to me he normally would not say.

The mother of my child is upset because I did not give her money for something that was not for my child but for her. We are not together anymore and we do not have a custody agreement in place. If I do not give in to her every command she will keep my child from me and then bombard my phone with texts from text apps where I have to continously block numbers. If she cant call me she will then use the child's phone to call and berate me. She will say things like I am causing my child so much pain, I am a horrible father, and that I do not even love my child. She then forces my child to say things he normally would not say, like "I don't want anything to do with you," "I'm done with you," etc. You can hear in his voice he's scared, and a lot of things are rehearsed, occasionally causing him to cry or have anxiety. Today alone she has called me over 25 times. I have tried mediation, but she will not start it. I am very worried for my child's mental status, as he's only 10 and already in therapy for anxiety. She will tell him anything to turn him against me, even though it is not true. She is doing everything in her power to control me.