CSA mistakes mean I have arrears

I have been dealing with the csa for 6 years , after offering my ex £80 a week maintenance she decided this wasnt enough and contacted the csa , who after many many lost letters and lost wage slips finally decided i had to pay £60 a week.

I have recently been made redundent and decided to go it alone and start my own business , I contacted the csa to explain this and was told not i wouldnt have to pay anything until i had books to prove my new earnings , which i soon found out was another one of their misinformed lies , so i then had to pay arrears which i have had to do many many times cause of their under trained staff.

Just before my end of year tax records had to be handed in, the csa contacted me and asked for my records i explained they were with my accountant and they would receive them in two weeks after an argument they agreed.

Four weeks ago i received a phone call saying iv overpayed them by £1400 and it will be refunded into my bank , today iv received another call saying out of the now £1600 iv overpayed they are only refunding £200 because i was late handing in my records , so they are keeping £1400 of my money , theft , scaming , above the law , csa has it all. I’ve got to the stage where i just laugh cause if i didnt id get myself arrested , i would never let my children go without , please please all parents if you value your sanity and cash keep away from the csa mafia .