Assuming the caller ID was not spoofed, this call is LEGIT. This company performs fraud prevention services for UWCU and maybe other companies. They provide you with a generic reference number on their voice mail. You call back, provide the reference number, verify your name (not any sensitive information) and they read the details of a recent questionable transaction. You tell them if it was really you or not. If so, you're done. If it was NOT you, they offer to freeze that account and then you need to contact your financial institution to make a fraud claim.