Moved to LiveSafe for better support.
Have you tried uninstalling the old Safekey from that machine in the normal manner? That should have been done before installing LiveSafe, I believe. I don't think you can change an existing Safekey account in the way you are asking, you would have to make a brand new one with a new email address.
Customer Service deal with account issues and Technical Support with technical questions and if they couldn't help at first ask them for escalation to a higher level. This product is relatively new so they may not yet be totally familiar with it.
Hopefully someone subscribed to this section will chip in here to help. I don't actually use the product myself.