What’s CSA rule about continued payments?

my son is 16 years of age, he has left full time education and starts an apprentiship on 1st September he told me that he would be going to college one day per week but when his mother realised that i had contacted the CSA he now apparantley attends college 1 1/2 days per week, he is being paid a wage and has left full time education. What are the CSA rules about continued payments, surely payments must stop????? i beleive that the CSA do and say what they want and act unlawfully toward us fathers who have paid regular payments!!!1