I think I received them earlier, like 4 or 5 hours ago. That would have been 3 hours and a half before they sent the message. I remember telling my guildmates I had 5,000K coins and that I didn't know where they came from (I had just completed 4 successful sea sailings, so I thought it might have been that).

One can understand from that that they realized they didn't write the same numbers as the ones they had sent. They panicked and changed the numbers in the e-mail.