What do you think I should do? Caught up?

Don't listen to her. It's about the court judgement and what's right for your son. You can respectfully say no by texting, emailing or calling. If you want to talk face to face, just say it as in any normal conversation. It's ok for your ex MIL to have visits but that's all. She has no say in anything else. Also, if you start lowering the amount, where will it stop?