How to handle an order flagged as medium fraud risk due to mismatched billing address?

[RewindUSA]

We received an order that was flagged as a medium fraud risk because the billing address didn't match the card's registered address (the customer marked it as the same as the shipping address). I messaged the customer about this and they provided a different address for the card's billing address, a PO box in the same state but in a town a few hours away. 

But I can't edit the billing address or verify it against the card information in any way? There are many logical explanations why billing and shipping address may be different, but how much should I bug the customer for their life story when I can't even verify anything on my end? Is the only option to be sure to cancel the order and tell them to try again? That seems clunky and obnoxious, and is likely to cause us to the lose the customer.

I don't understand the point of having fraud analysis that tells me something about the order with no real actionable solutions to help protect us in the case of a fraud claim. I recently lost a big chargeback claim despite providing call and text logs and a long and detailed write-up about all the ways I tried to confirm the order was legit, and rather than the bank taking the hit WE lost our product AND the payment AND a chargeback fee... so once bitten twice shy. What to do?

Thanks for reading

Full fraud analysis:

1. Negative
   Billing street address doesn't match credit card's registered address (Not sure if the name on the card is validated to the customer or not)
2. Negative
   Billing address ZIP or postal code doesn't match credit card's registered address
3. Neutral
   Some characteristics of this order are similar to fraudulent orders observed in the past (this is vague and unhelpful)
4. Neutral
   Card Verification Value (CVV) isn't available (Isn't that the security code? how could this be unavailable? Why would shopify accept a CC payment without verifying this information?)
5. Neutral
   Location of IP address used to place the order isn't available
6. Neutral
   Distance between shipping address and location of IP address isn't available
7. Positive
   There was 1 payment attempt
8. Positive
   Payment was made with 1 credit card
9. Positive
   Billing country matches the country from which the order was placed
10. Positive
    The IP address used to place the order isn't a high risk internet connection (web proxy)