Bad treatment you single parent and you dont have money

I'm very disappointed in this school. I app**** for this school since her sibling also go to the same school.Since last year they are sending me up down and not treating me fairly just because I work on the retail.I went to education they gave me letter to go there but the school doesnt want to accept my kid because they want to discriminate us because of how much we earn.That admin is busy checking how much pay as school for the current sibling I don't understand where does that have to do with new sibling as nothing I owe to the school.I thought every child have right to school irregardless of how much you earn but this school is treating me otherwise. The painful parts that lady she's the one who send me at district when I come back with a letter she doesn't want to help me