I re-did my manual/contract. Parents must pay me at drop-off for the week on the first day of care or they do not receive care. Noted in there as well, it's a $20/day for any late fees (to prevent parents from doing so). SO far, no parent has paid late, and I'm ready to turn parents and kids away if I don't get my pay at the beginning of each week.

For the child misbehaving on your property, I would fix the problem if mom isn't willing to do so. Also in my policy, it states that parents and children alike must respect each other and anyone on my property. For people who don't respect others and my property receive 1 strike (it's a 3-strikes and you're out - no 2 weeks notice). And I will let them know that this behaviour is unacceptable.

I would try this - and if it doesn't work after a week, give them notice. It will only continue.