Hes got the calculation from them in writing with my salary on it

I pay him CSA payments Im not happy they disclosed my earnings to him at all, he has no reason to know, at the end of the day they are a agency and should be trustworthy, all they need to tell him on my salary they have calculated that the payment will be XYZ

Well he says he has it in writing and I doubt he would be able to work it out, so I have made a start of a complaint and am sending an official one and then taking it to information protection ombudsman.

After a conversation with my ex husband he informed me that the CSA told him how much I get paid annually, and proceeded to tell me , and then told me he also had it in writing. Can the CSA divulge my earnings to him, I thought it was confidential between myself and them have they breached Data Protection Act Any advice would be helpful Thank you