why can't they find the problem??? on 2010 Honda Insight

2010 honda insight 8045 miles on the odometer
check engine light on.
dealer repaired leak coming from evaporation system and replaced valve. system reset.
next day, check engine light on,
same defect shown.system reset, next day, check light is back on, going back tomorrow monday

Asked by for the 2010 Honda Insight
1 answer 1 comment
What is the trouble code number?
no number' just check emission system.

but they did get it fixed on the 4 try.
i got spidered. the line to the fuel canister had a web sack in it.