How long have you had the flood insurance?
Apparently the Federal Flood insurance program will not cancel you if you are already insured unless your house is totaled by a storm surge then they may not renew-just tell you to take the money and run for high ground.
But if I were buying property down here I would make it contingent on being able to buy federal flood insurance.
Even though we have owned since 1998 - we didn't purchase flood insurance until after Dennis - hate to admit didn't give much thought to it since we are so high and the mortgage company didn't insist on it.