Abolish the CSA

My partner has been having trouble with the Csa 2 years now, he's never missed a payment, he changed jobs and was on less wages and the Csa still hounded him for the full money, which he didn't have, he sent in all his proof of earnings and now he owes loads in back pay. The Csa always say they will call him back and they need do, they are very rude to him on the phone. He's done everything he should of done, but they are still hounding him for more money, the Csa say one thing on the phone and then that changes in the next phone call. They really havnt got a clue what the hell they are doing! Then there is my separate case on my sons father, never paid a penny and the Csa just fob be off saying they can't get hold of him.he hangs up the phone everytime they call, So I still havnt had a penny from my sons dad. They seem to pick on the fathers that are trying to do right by there children. I have sent a letter of complaint to Csa and never heard a thing back either. So so angry think I am going to call them now to find out what's what, sick and tired of getting fobbed off for all theses years