Chargebacks

We are getting a med/high risk fraudulent orders some of these all the card details match including the card address but are being posted to a different delivery address. These are high value items that the bank would flag before the order was processed unless it is the persons card?!. We also also as per advice on shopify for proof of address of which we have done and the customer has replied, even with this it goes in the customers favor through shopify.  We are at our wits end and losing a lot of money after following the process. Any advice would be appreciated.