WARREN, Mich. -

The trouble started early Thursday afternoon when a plumbing problem put some bathrooms off limits at Carlson Elementary in Warren.

More than 500 kids were sent home from school 3 hours early.

On Friday, 9-year-old Mikayla got off the bus in Warren and walked home with no problem. However, there was a big problem on Thursday.

"I went home and the door was locked, so I was sitting there trying to think what to do," she said.

A few minutes later she went to a neighbor's house and called her mother, Shelley Heronemus, who was at work.

"I was shocked because I didn't know anything about it," she said.

The school had used robocalls to alert parents about the early dismissal. However, Heronemus wasn't home to get the message. Moreover, the power was out.

"You can't really rely on an automated system to get to everybody because there are flaws in that. I just fell like personal calls maybe would have been more effective," the mother said.

School administrators say they had to act quickly because they had too many kids and too few bathrooms. They robocalled before nature called.

The school had several emergency contact names and numbers for Mikayla but typically robocalls go to only one or two numbers. In Heronemus' case, it was her home phone.

"I'm definitely going to call the school and make sure that they have my cellphone number as priority," she said.

The Van Dyke Public Schools district says drivers waited at least 5 minutes at each stop. Fifty to 60 kids were bussed back to the building after finding no one at their homes. Teachers tried to call the parents directly.

"I was pretty upset," said Heronemus. "I didn't even get an apology."

Mikayla's family thinks the school should handle early dismissals differently. The assistant superintendent stands behind the procedures they followed but she adds, "We regret that this student did not arrive home in the manner her parents would have liked."