Shirley calls the Woodbergs but is told that Nadine is out "babysitting." Shirley hasn't assigned a job to Nadine, so she realizes that Nadine has once again started to "babysit" without giving Shirley a cut of the profit.
Shirley calls Melissa, who says she knows where Nadine is. They drive there and Shirley and Melissa pull Nadine out of the car and punish her.
Then we see who Nadine was "babysitting" for - Shirley's father. Thus Shirley ends the Babysitting Service, presumably avoiding legal consequences.