Can you contest the amount CSA makes you pay?

My wife and I separated in march and after refusing to let me pau an affordable amount she decided on the CSA route. They asked for 76 pounds a week which I couldn’t afford explaining to them that my unemployed wife has 2 children while I had 1 with me and had to keep a roof over both out heads and only earn 300 a week. After fighting as long as I could I now have an attachment of earnings order for 96 a week including arrears. We will now lose our privately rented home as unaffordable and have no idea where to go or what to do. Is there a way of contesting this amount so we can afford to live?