"While we are unable to provide detailed information on how we link related accounts, please know that we have reviewed your account on the basis of the information provided and regret to inform you that it will not be reopened."
This happens more frequently: Google says this all the time, based on posts here; Amazon now does the same thing; even apartment rental companies will say "you've been turned down on the basis of this report that we don't know the contents of."
If your company can't reveal specific reasons or steps behind why an action was taken, DON'T TAKE THAT ACTION. Even my credit card issuer will tell me exactly why my card was flagged and they deal with ACTUAL MONEY. All these statements do is infuriate customers, create bad press, and drive away other customers. Scammers will just back up, look at their entire operation, and hammer away again with 300 new accounts so all you've accomplished is pissing off customers who want to do business with you.