cannot log into account

After entering username and password I got another page telling me that the info didn't match (which was not true as I made sure everything I entered was correct), and asking me to verify my ATM card number, PIN, and account number.  I did that, and the page reverts back to the login page.  I called Citibank and was told there was nothing wrong with the site but if the browser is Safari it might not be compatible.  Which is ludicrous since that's what I've been using all along and didn't have a problem prior to this.