i have same roach infestation problem, and pandan leaves doesn't help at all. then the roach problem got worse, their cousin moved in too, the lizard.
the event unfolded unexpectedly.. after just 1 week, the roaches are gone, presumably cannibalized by the lizard. i have to put up with lizard droppings here and there, but not 1 roach is ever seen again. after 2 more weeks, no more lizard dropping. i assume it has migrated to greener pasture.
problem solved, "naturally", for now. till the roaches move in again.