Why won’t the CSA discuss how it calculates arrears?

In 2009 I referred myself to CSA who told me what to pay and I paid. I had sold a business and the proceeds were sitting on deposit earning 2%. Then I bought 4 buy-t-let properties with the money and had loans.

Tribunal ordered i pay maintenance assessed on capital value of houses. Appeal directed re-hearing in 2012. New Tribunal ordered assessment based on income from business. That yields circa £4K-6K per annum.

CSA calculate my liability at £33,000 from 2009 -14 yet I am only earning £4,000 per annum. They refuse to give me their calculations as to how I can owe £17,000 ‘arrears’. They have now gone to County Court (without serving me) and got I Order I owe £17,000.

I am going mad – how can I make then disclose their calculations – they have refused for four years to ever meet to go over my income from my Accounts and tax returns.

What can I do? Help!