When you pay for AdBlock Premium, we store your email address on our secure server so we can verify your purchase if you lose your License Key. We may, very occasionally, send you an email if we have something important to tell you. It will always be easy to opt out of future email from us. We will never, ever sell or give your email address to anyone for any reason whatsoever. We hate junk mail, too.
We also store the last four digits of your credit card number on our secure server. This, along with the payment amount and date, helps us to find your payment again if you ask for a refund. We don't store your full credit card number, expiration date, or verification code.