Signed off work depressed at the CSA’s actions

I have been with my parter 3 years and he has a child from when he was 16. the mother has another child with another man and she was 22 when got pregnant. (a lot older than my partner) She now uses the csa to control us. I am now on antidepressants from this and signed off from work.

Please help. WE have paid all his life. but she gave wrong addresses etc and we all of a sudden got a deductions of earnings order of 40% arrears of two grand apparently but then she decided to go back private so we had to……….but she wouldn’t close the case so its still hanging over us.