This has broken me

I have three children, three boys. two with X wife, one with another parther. I have a great relationship with my x partner, pay for lad direct, and have a great relationship with him. I was paying csa for all three willingly. my x closed her case, my x wife didnt, thats fine. but 15 months ago, she met someone else. she told me, byemail that she didnt wantme to have anything to do with the boys any more. this broke my heart, i went round, she threatened me wit the police etc. she then wrote again saying she didnt want too see me again but also didnt want any money off me. she has since disappeared.

i instructed a solicitor to trace her and we think we have found an address. however, she is not responding to court documents re access.. however, thats for another day as its ongoing. I changed job. etc, stopped paying csa, as my other x was happy with arrangement and x wife said she was closing the case. my new employee got a letter last week asking for my salary details as they want to deduct money for arrears.. I rang them immediatley and have beein in dialogue with them. however, whilst they acknowledge my x said close the claim, they cannot trace her. they have written to her, emailed her, and tried to call her but they cant trace her.. however, because of this they cannot close the case and are now threatening to take out up to 25% of my salary to cover arrears.

this has broken me. if they do that, I cant continue my court action, she does not want this money. she written to me to tell methis and she has disappeared. however, the csa say they need to pay these arrears.. despite her not wanting it and not knowing where she is. this will break me , totally. i would pay fo rmy kids. i have no issues. i have written confirmatino of letters, emails etc sent begging to see my children. however. no response bar the email from ehr saying she is closing the case . can the csa do this to me, even though they cannot trace her??? please help. and sorry for typos. i am typing on a phone. any help or advise would be appreciated.
thanks