According to the Federal Emergency Management Agency (FEMA), scammers continue to target the victims of recent hurricanes Harvey and Irma through robocalls in which people receiving the calls are being told that their flood insurance premiums are overdue and that they must pay the scammers immediately to avoid loss of insurance coverage.
You can never be sure whenever you receive a phone call whether or not the person calling you is legitimate and even if your Caller ID indicates that the call is from a legitimate source, your Caller ID can be tricked through a technique called spoofing to make the call appear authentic when it is not.  In this instance, if you receive such a call and wish to confirm whether or not it is legitimate, the best course of action is to contact your insurance agent or your insurance company directly at telephone numbers that you know are legitimate.  If you have a flood insurance policy with the National Flood Insurance Program (NFIP Direct) you can reach them at 800-638-6620.