Particles not interacting with .stl Walls for compaction of two particles

Hello all. I am fairly new to LIGGGHTS and I have been trying to run a very simple simulation of two spheres in contact under load by method of compaction. I am simply using two .stl walls (bottomwall and topwall) and compact the two spheres my moving the topwall and keeping the bottomwall constant. I am able to view the simulation in paraview and I see the top wall moving; however there is absolutely no interaction with the particles.

My input file:
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#first_input file
units si
atom_style granular
atom_modify map array
boundary m m m

newton off
read_data part_arrange.sys
communicate single vel yes
neighbor 0.001 bin
neigh_modify delay 0

group A type 1

#Material properties required for new pair styles
fix m1 all property/global youngsModulus peratomtype 1.0e8
#E=0.1GPa units Pa
fix m2 all property/global poissonsRatio peratomtype 0.3
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.2
fix m4 all property/global coefficientFriction peratomtypepair 1 0.2

#New pair style
pair_style gran/hertz/history 1 0 #Hertzian without cohesion
pair_coeff * *

timestep 1.0e-4
fix ts_check all check/timestep/gran 1000 0.1 0.1
fix gravi all gravity 0 vector 0.0 0.0 -1.0

#granular walls
fix topwall all mesh/gran topwall.stl 1 1.0 0. 0. 0. 0. 0. 0.
fix bottomwall all mesh/gran bottomwall2.stl 1 1.0 0. 0. 0. 0. 0. 0.
#fix cylinder all mesh/gran cylinder3.stl 1 1.0 0. 0. 0. 0. 0. 0.
fix wall all wall/gran/hertz/history 0 0 mesh/gran 2 topwall bottomwall
fix F_movetop all move/mesh/gran linear 0. 0. -0.0002 units box topwall 1

fix integr all nve/sphere

dump walldmp all stl 2500 post/Wall-*.stl
compute comp all pair/gran/local pos force contactArea

#insert the first particles so that dump is not empty
run 1
dump dmp all custom 2500 post/dump.first id type x y z ix iy iz vx vy vz fx fy fz radius
#run
run 500000 upto
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Here is my read_data file. I have used mass scaling where my density is huge so that the simulation time step is reasonable (is this ok?). The density should be 1210 Kg/m^3

part_arrange.sys
==================================================================================
LIGGGHTS Description

2 atoms

1 atom types
0 bond types
0 angle types

-0.5 0.5 xlo xhi
-0.5 0.5 ylo yhi
-0.5 0.5 zlo zhi

Atoms

1 1 0.05 121000 0. 0. 0.025
2 1 0.05 121000 0. 0. 0.075
==================================================================================
My .stl files are simply two planes. One at z = 102e-3 m and one at z = 0. I realize this is a very simple simulation so I am guessing I am missing something very simple. In any case, any help would be much appreciated.

Regards,
Sean