Ex on child support

Okay so my ex has been on child support for 2 years and he has missed some months on it. He takes our son maybe 3 weeks during the summer and every other weekend or so during the school year. He only bought our son shoes and some clothes for school because I told him he just needed some shoes otherwise I don't get anything from him. He pays $225 a month. Now I got this message from him this morning and I don't know what to think about it. I don't really need the child support money as I make out okay but the fact he's been on it 2 years and wants to complain now is what gets me. He used to have a decent job when we started child support and I guess now not so much. I didn't know that he was in school and only did delivery part time. Aren't they supposed to report changes themselves?

I'm in Florida