Been there and I would never do it again. I say get out as soon as you can. Without a written separation agreement on who is responsible for daycare fees, you could have a problem. First thing I would do is ask for a copy of whatever agreement they have regarding childcare fees. If they dont have one, then you need to establish upfront payment. I would be asking for fees for the whole month to protect myself. I agree with others that you cannot deny a parent access to the child just because mom says so and as for the grandmother, have they indicated in your paperwork that she is allowed to pick the child up? Either way I think that you should send home a letter to each parent stating that given the circumtances that if they want the child to remain in your care that you will not release the child to anyone other than a parent. If they dont like that, they can leave.

Ultimately my best advice is to give notice to this family. Its only going to get worse before it gets better. The family I had divorced quickly enough with little issues but the issues came a few years down the road when dad got a girlfriend and decided he wanted shared custody instead of joint.. that battle went on for over a year and it was the little boy and me who were caught in the mess of it all. I was trying to please everyone and dad got downright nasty to me because he thought I was on mom's side and the only side I was on was the kids.