#3 - June 14, 2010, 11:52 p.m.
As Crepe indicated the messages you are receiving would be phishing attempts. If you are receiving whispers please right click on their name in the chat window and select "Report Spam" that will not only ignore the account for the duration of your play session but also send a report up for review.
As for a trial account attached to your Battle.net account you can contact our Billing and Account Services department, they should be able to help.
You can call 1 (800) 592 5499 (1-800-59-BLIZZARD) 7AM-8PM (PST/PDT) for live representation.
Australian users should please call 1-800-041-378 if the standard 800 line does not work.