Not that the situation is this drastic, but it might literally be easier to move than get rid of the Aegopodium. I tried once, dug up 3 giant (leaf size) bags of soil from the garden, removing the top 6 inches or so & didn't put a dent in it, just invigorated it. That was before I discovered smothering, which is what I would do if I ever have the misfortune to encounter this awful plant again. No plant can live w/o light.