Child support is late ….

So I’m new to this , I’m not really sure what to do about late child support. I would reach out but I’m nervous because typically I get hospital responses to everything I say or ask my sons father. He is in no means cooperative or easy to deal with it 10 days late and I’m not sure what is should do . Should I tell him I never received it and if I get a hostile response report it ? I use it towards rent typically it 400 but it’s better than nothing. I don’t wanna seem like I’m up to no good , I’m really skittish when it comes to this stuff. Any tips

He’s self employed 🙄🙄

so idk how they will handle it , I will contact them the beginning of next month I guess I wasn’t sure how long to wait