If you have a file (or files) that you've submitted and are coming back clean, please contact support. We can look into the submission and work with development, if needs be, to get a second look on the file. We're human, and, as much as we try not to, it's possible that we missed the detection in this file when we examined it.
Please have your tracking number handy when you call in, as the agent will need that to investigate further.