My dust bin has fallen out two days in a row.

Hi Bobbi

It sounds like any of the following

• loose tolerances or ware on the plastic guides holding it in place
• loose release button
• something it runs over pulls on the dust box, and removes it

Check if the fit of the dust box has become looser over time, and if there is a part of the floor that's unlevel and could catch the box, disconnecting it.

If so, consider using a small layer of tape to add some thickness to the mounting points to better hold it in place