Bathroom Counter top loose from wall

[MTHook]

Fairly minor problem with the half bath counter top being loose from the wall. When they built the unit they put 3 screws into the 3/4x3/4 block under the top. Those only hit the wall board and just spin so tightening isn't working.
Being the bright guy I am, I ran out and got a couple toggle bolts small enough to fit thru the 3/4 block. Drilled the 3/4 block and of course had to make a plate to cover the block and drill a small hole for the toggle bolt itself. I got the large holes drilled, installed the toggles drew the bolts tight and the toggle fell apart.
I forgot that these things have foam instead of fiberglass so the toggle didn't open up.
So I need an idea what to do next. I'm thinking about shooting some gorilla glue into the foam/wall board with a wooden peg, let dry and screw the thing together. Hopping for a better idea.
Any ideas how to get the foam cleaned out behind the wall board, see the drawing I need the area between the dotted lines

[Long & Winding road]

I say use some toothpicks and wood glue. If the Gorilla glue drips you have a big mess you cant get rid of, wood glue you can wipe it up within the first hour or two and your fine.

[The Gritz Carlton]

Liquid Nails...thick, doesn't run and will stick the stink to crap. Use a caulking gun and shoot a little between the surfaces. It will never come off again.

[MTHook]

Liquid nails yuck. I love that it works, hate that I seem to have it on my hands for a week or two after using it no matter how careful I am.


The problem I have it that there is only an 1/8 or less between the wall and counter top so I really need something to pull them together hence the toggle bolt.
I need a way to clear the foam insulation from around the inside of the hole between the outside wall and the wall board so the toggle will open.

[The Gritz Carlton]

The "winged plastic" or "hollow wall" anchors should work. They should pull themselves through what little styrofoam they encounter.