I'm so sorry to hear this has happened with your contacts! I have taken a look at your account and can see you've spoken to our support about this experience. In fact, one of our Support agents has sent you a follow-up email today. Have you received this email at 3:45PM? If not, I'd be happy to share their workaround of changing the file format to .xls or .xlsv and trying to upload it again. Does changing the file format help?