WHoa! Skype? OMG Tell me they didn't use Skype to communicate internal information while running the business. OMFG
Could be worse, could have used IRC. Just sayin'

They should have had a private internal chat server with mandatory encryption, no file sharing ability, and no external access. You could even make a case for retaining every message for a 7 year period.
Not skype. It's a public cloud service.