They are taking 120 per week from my wages, I get before tax: just under 300 per week

Hello people, My name is [removed - dx], I am 26 years old., From Bedfordshire. I have 4 kids (please don't judge) with 3 mother's, 2 of whom we are good, my youngest child's mother always causes issues if I give her money like the other 2, she is not grateful and wants more, which is unfair to the other mother's, she went to CSA and claimed I never got involved with my child and also went to my work place and put in a complaint, claiming I was breaching data protection a case was brought up but I was okay as she kept changing stories. But it got to me mentally and I eventually quit my job, I took a few weeks out of work and worked in a new place now CSA sent me a letter saying they'll take 50 pound each week from my new wages which was less than I was giving her, then I received a new letter stating they was going to take 120£ a week. At the time I was living in a shared house and could barely afford to pay rent with this new job, let alone pay for my other kids, I ended up working overtime everyweek and loosing out on sleep, so I could hardly see my children, this started to affect my health, my life and was making me really weak, I wasn't eating. I rang them and pleaded with them, supporting my case with what I could and saying I couldn't afford what you was taking, but they had made it so it came straight out of my wages, I couldn't pay a single penny to my rent, I couldn't afford food, or even to pay for my other children, I eventually became homeless and turned to alcohol (iknow that isn't great, please don't judge) with no home, I lost my job (which was night shift) I had nowhere to go. I've had various mental health assessments also. Until I met a very old primary school friend and he took me into his home up north in Lancashire, he housed me for a bit while I started work, and got myself a place.. things was going okay, my mental state really improved. Until I received another letter this morning, stating they will be taking even more money. Is there anything I can do, I'm sure it is illegal to make someone feel so low and homeless. If anyone can help that would be much appreciated, even if it's something small.... I just don't know what to do.