First, flood vendors are required by law to guarantee results, so see what that gets you in terms of fines, etc as mentioned above, Ask about having your other properties rerun at no charge now that you know about this error.
And lastly, as the others have said, you correct going forward. Even if you could get years of insurance retroactively, what would it get you? The violation still stands-that cannot be erased, and there was no flooding. It would not resolve anything.