fall through the cracks

fall through the cracks
slip through the cracks

(to be forgotten, overlloked or missed by a system or program that was organized to deal with a particular situation; to not be dealt with by a system that is designed to help you or to stop you doing something) — выпасть из поля зрения; оказаться без внимания, поддержки или помощи; быть /оказаться упущенным (кого-л. или что-л. упустить, проглядеть, проворонить; недоглядеть)

If you think about the words, “slipping through the cracks,” it will make sense metaphorically. If someone has slipped or fallen through the cracks, he has fallen away from people who can now help. It means the person has been forgotten or was neglected. (David W Millers)

Examples:

…..Little details often slip through the cracks.

……Too many neglected children are slipping through the cracks. (MM)

…The class sizes were large, and it was easy for some students to slip and fall through the cracks as one on one teaching was near to non-existent.

…In spite of excellent quality control, some faulty goods always manage to slip through the cracks. (OALD)

...The medical system is here to help people. Some people, because of their circumstances, are not able to get the care they need and fall through the cracks.(David W Millers)

…These kids are not old enough for jobs. Nor are they rich enough for camp. They are school children without school. The calendar called the school year ran out on them a few weeks ago. Once supervised by teachers and principals, they now appear to be in “self care.” Like others who fall through the cracks. of their parents’ makeshift plans—a week with relatives, a day at the playground—they hang out. ( Wyrick)