Systems and methods for preventing fraud in an IP based telephony system include noting when an IP based telephony device sent to a new customer is not installed and registered with the system. If a new customer never attempts to register a device which was sent to the new customer, the system will assume that the new customer submitted false or erroneous address information. A new customer is prevented from taking any actions that would result in new charges until the new customer has registered an IP device sent to the new customer. Likewise, the system will act to prevent a phone verification service from reaching a new customer at his newly assigned telephone number until after the new customer has registered an IP based telephony device sent to the new customer.