The system matches organization names to ensure that colleagues are all linked to the same company. If your company's name is on your Meeting Mojo Customer Account, your colleagues will be added to it - this means they will not appear in the attendee listing!
If your colleagues will participate in 1:1 meetings, use a spelling variation of your company's name on the import spreadsheet. If you have already imported them and they have disappeared, go to your Account area by clicking here and delete them before re-importing.