This is how Delta tells you to shut up

So your employee sells your products at a wrong price. You bill the customer more than twice of what he has accepted to pay. And when the customer brings that up and insists that it's not correct, you write an email as beautiful as this:

Thank you for your additional comments concerning our recent exchange of e-mails. We try to be responsive when any problem is brought to our attention, and we regret you are disappointed with our reply.

Mr. Matzner, we realize the situations you encountered left a very negative impression. As you requested, we have again reviewed the matter to see if we overlooked anything that might support a more favorable conclusion. Unfortunately, there is nothing we can add to what has already been stated in our previous correspondence.

Thank you for the opportunity to give this matter our final review. Any additional correspondence will be kept on file.

Thanks for the invitation, Delta. You'll definitely hear more from me to keep on file.