CSA miscalulate my payments and leave it until I build arrears to tell me!

May 5, 2017

In 2009, I received a letter from the CSA stating that I should have been reassessed with regards to the payments I was already making for the past ten years.after calculating my income I was told that I should have been paying more,and that I was now 23,000 in arrears.after pointing out to them that they had used two years salary,instead of one.I was then informed my arrears were 11,500.which I have now paid off.I agree that I had to pay CSA,but they have known my address since 1990.so why didn’t they contact me earlier.complete cockup.