Got A New Client, Wants A New Way To Pay, Need Help With Contract

[daycare]

So I landed a new kid who will take over one of my families while out on maternity leave. The child will be temp, so it all works out perfect.

So the dad's company will pay childcare pretax and the company will mail me the check direct. I will be paid every other week. So here is the thing. I have never delt with this before and I don't know how to apply all of my current policy late fees?

This is what DCM told me.
Need invoice 1 week before payment
payment takes 5 days to go out

I know that the dad cant controll when the check comes, once they leave the office, so how do I make sure that I still get paid on time?

I did tell the DCM that she and DCD would be the one responsible for all of the payments??Have any of you ever delt with this before? What would you write up? How would you handle this?