How come I owe so much?

My daughter started work as an y I owe 5000 apprentice hairdressers and 16 after leaving school the csa was informed and I stopped payments with a dispute as to just when I should pay.

I never hears from them until 8years later when they now say i owe 5000 grand for the time from hear leaving school untill she was 19 even though she was working full time.