Note: This module is no longer supported by Telesign. In WHMCS version 4.3 the SMS verification function is not available.
Telesign is a telephone and SMS verification system that can call or message all new orders before the payment page to check their authenticity, thus reducing the likelihood of fraudulent payments and the resulting chargebacks.
You can choose whether clients receive a pin number in a telephone call or via SMS (or even give clients the choice themselves) which they then enter into your website. Numbers can also be whitelisted so that clients only need to perform the verification once.