If you review your Cardholder Agreement, there is a good chance that the card issuer has the right to put a hold on your account.
However the demand for a form to release your tax returns is frankly highly irregular and a red flag that you should have someone scrutinize the demand for information. Furthermore the high pressure that you must immediately fax sensitive financial documents sounds eerily like a form of phishing. One thought on why no U.S. Mail is that the demand is coming from outside of the United States (which Electronic and faxes could redirect to mask). My recommendation is that you be very very careful with this demand for information as it appears to have the hallmarks of fraud.
Answered on Jun 24th, 2012 at 2:15 PM