This thread could be used in modern business courses of how to not handle a situation like this.
I've never quite understood how businesses like Canada Ammo and FOC could suffer a data breach and then proceed to mishandle both the technical and public relations sides so utterly and completely that they essentially rolled a live hand grenade into their own store and hoped for the best.
GunsNotPuns Rule of Data Breach Crisis Management 1: Resolve the technical issue. Immediately. If you can't, stop taking orders.
GunsNotPuns Rule of Data Breach Crisis Management 2: Immediately get ahead of the story by emailing all potentially affected, as well as using their official platforms on places like CGN and ### to inform everyone of what happened and what they've done to resolve the situation. Offer something symbolic but meaningful to everyone.
Yeah, people are going to be angry and inconvenienced, no question about it. No one, however, is going to question your willingness to do the right thing. Long after people forget the annoyance of having to get a new credit card, they will remember that you stood up like men and took the shots.
But hey, what do I know? For years I managed a multi-million dollar business line with over 120 employees and dealt with public issues regularly. Every phone call I had with the public that started out angry, ended up with both of us at least satisfied that something was being done. Consulting services available.