Hi jackzgh,
I'm sorry to hear about this - and I imagine it's quite upsetting and frustrating. Have you been given any information about what the 'infraction(s)' may have been? I'm going to assume that you were not actually caught cheating, but can you think of anything that you may have done during the Test that would have been viewed as 'illegal' (re: were you talking out-loud, frequently looking away from your computer screen and note-pad, did you take a phone call or interact with anyone during your two 8-minute breaks, did you discuss any of the Test questions during your breaks, etc.?)?
GMAT assassins aren't born, they're made,
Rich