Could it be my sewage ejector basin leaking

[mycao1999]

I have a basement sewage ejector pump. One day, the sewage water
overfilled at the
outside of the lid of the pit, and the shower water didn't drain any more.
Obviously the
sewage ejector pump was not working. But after a couple days, the water
was not seen at
outside of the lid, and the shower water drained down. After that, I took
short shower
twice, each about 5 minutes. The shower water drained down and the sewage
didn't
overfill, even though the pump was still not pumping (each time, I sent my
husband
watching the ejector pump while I was having a shower). Then a couple of
days later, my
daughter had a much longer shower, but this time the sewage water
overfilled again at
the outside of the lid of the sewage ejector basin, and the shower water
didn't drain any
more. At that time, we found that the electric cord of the pump was
unplugged by
accident without being noticed by us. After we plugged it in, the pump
immediately
pumped the sewage water out. That means ever since the first sewage water
overfill, the
ejector pump was not working. But the sewage ejector pit seemed lowered
the water
level by itself unless the pit was filled with water too quick. Where did
all those sewage
water go when the pump was not working? Could it be the sewage pit has
cracks or
holes to allow the sewage water slowly leaked to the basement underground?
That looks
very much like the case. If the crack or hole is on the bottom of the
basin, even if the
pump is working, the sewage water below the pump float level could still
leak to the
underground of the basement. If that is the case, what damage can it be?
Should I open
the lid and have a look at the basin to confirm it? Should I have a
plumber to check it and
fix it?

Thank you very much for your kind input.