Top shelf slides off rollers

the top sliding shelf comes off the rollers

Model dishwasher: PLD2855RFCO

The white rollers look OK, but are crooked - - looks like the screw holes have become larger from the sliding and have tilted downward. If I get new screws, the holes are still too big and will also slip.

How can I straighten the rollers and keep the rollers from slipping off the track?