If you make a single purchase, but notice a double charge on your bank statement, don't worry, this is most likely an authorization (pending charge), rather than a real charge.
For example, when making a payment by credit card for certain services, your credit card company may authorize your card before the actual funds are taken. If this is the case, the authorization appears on your bank statement in addition to the real charge. But don't worry, as the authorization charge should disappear from your bank statement within 3-5 days.
Of course, feel free to reach out to our support team at email@example.com if we can provide further clarity regarding any charges on your account.