Ok so Z is at 2 and the surface of the material is somewhere lower i.e more negative so -3, -4 etc.
To test this out, do not use a tool etc, just verify first that when you ground the touch plate the PROBE led lights up, before that though make sure you have the PROBE input set correctly in ports and pins, probably is though.
Now, presuming you are in inches....
Enter in MDI
G28.1 Z-4 F100 and press enter
The Z axis should start moving slowly downwards -does it??
If yes then it should stop as soon as you ground the touch plate i.e. make it think it has found the tool.
No tools are needed, its safe and easy this way

report back
