CSA have let me down by not getting my ex to pay

I have been let down by the child support agency. I am a single mother of 2 kids under 10. I work up to 50 hours a week and struggle to financially support my kids, when my daughter was 2 and my son was 5 I decided to go through the child support agency as there father refused to contribute. They decided he should contribute £120 a month and even thoigh it did not cover my childcare fees at least it was something. For 6 months he paid it then stopped paying telling me I would never get any money from him. csa called me at work to ask me if I still wanted the money, which I replied yes, so they said they will attempt to receive payment.

1 year late I cal them to ask about the case and they were shocked that I had not received anymore money. Thye then decided that as he was a self employed electrician who was a director of a company that I should receive more. 5 years later and child support arrears of over 10,000, they ask me again if I want them to claim for the money I again reply yes. I am then informed by them that I most lokely will not get a penny but they will try. I then receive a letter saying that I will need to write them a letter detailing why they should try and claim for the monies. I am not entitled to any benefits and housing support, I have a boy and a girl and can only afford a 2 bedroom, which is costing me 1100 a month exclusive of any bills and I am in >10,000 pounds in debt. I am still awaiting a response from them. What was the point? I feel they need to be more stricter with these selfish parents and support parents who are trying. I am just so tired of fighting tbh.