The reasons that it won't eat the bugs may be because the bugs you try to feed it are dead.
The thing is, that this plant will only snap if
- two (or more) of the small hairs inside of its' leave will be touched.
- the same hair is touched in a time period <
- Moreover, it will secrete the eroding enzymes only if the hairs inside will be touched constantly (i.e. if the bug inside will be trying to escape).
It does it mainly to conserve energy, to not be triggered by any spec of dust that lands on it, because the snapping function does require quite a lot of energy, which in the natural habitat of this plant is scarce (that's exactly is the reason it traps bugs - to get more nutrients).