Legally, What Can I Do About My Ex Not Assuming Responsibility Over Our Child?

So my ex-husband has a history of always needing financial help from people. He was doing good for a couple months in which he didn't ask anyone for help but after his car broke down and unable to work because of it (Uber), he's been needing help. It's groceries for our daughter ("so she can eat on the diet she wants"), or internet bill ("so Im able to contact her") or whatever else. I know that his father pays for his rent and other things.

Alongside with that, he's just very problematic, whenever he doesn't get help he goes off on everyone and threatens to tell our daughter that people want to keep them away from each other because they don't want to help him. So he uses her as a weapon to get his way.

In our parent agreement, he is supposed to pay 50% of everything that she needs. The last year he paid pretty much absolutely nothing that we were supposed to split. Leaving the financial burden on me.

Honestly I cannot deal with this for another 9 years. Along with the fact that he's just very ungrateful, what can I legally do? Do I fight for more custody or what realistically happens if I bring this to court? I am tired of always assuming his responsibility and being seen as the villain.