How Slamming Happens
In the United States, local carriers have been responsible for distributing telephone numbers to individuals and businesses since AT&T split up into local and long-distance carriers as a result of deregulation. Orders to change long distance carriers would be submitted to them, and the local carrier would make the change. In the most common scenario regarding slamming, an employee of a telephone company (usually a telemarketer making outbound calls to prospective clients) would submit an order to change carriers to the local exchange carrier without the approval of the customer.
In the United Kingdom, landline telecommunications services were provided exclusively by BT until 1984 when the industry was deregulated, and the number of independent operators providing fixed-line domestic telephone services increased. Similar fraudulent sales practices have been alleged by British customers who claim that their landline service has been switched to a new service provider.
Slamming can also occur when someone is invited to take a survey or enter a contest. The contests or surveys are usually general in nature, and the participant is unaware that the "small print" on their entry is an authorization to switch their telephone service to another carrier.
Another common sales pitch leading to slamming involves misrepresentation of the slammers as account agents of the victim's current carrier, offering better rates or a free upgrade to existing service. Slammers using this pitch may even operate by sending bills attached to the victim's existing carrier's bills, further perpetrating the illusion of an upgrade to existing service rather than an unauthorized service switch.
Slamming has traditionally meant the selection of another long-distance carrier without the subscriber's consent; however, as the US market has expanded, and choice of local long-distance service and local service providers has increased over the last 10 years, there have been some instances of slamming for those services as well.
The problem has not been limited to landlines. In Britain, complaints have been received by OFCOM relating to mobile telephone contracts being renewed without the consent of customers.
There have also been cases of slamming for secondary services (such as voice mail, etc.), or of mobile telephone companies using private data to switch customers onto landline services provided by their subsidiaries.
The move by many wireless companies in the US from an unlimited data plan to tiered data services has led to a new form of slamming, consisting of changing a customer's unlimited data plan to a metered plan without informing the customer. This can happen when a customer makes an unrelated change to the plan such as adding an additional line. Verizon Wireless, which has been cited for other outrageous and unfair practices in the past, has been particularly aggressive about this recently.
Read more about this topic: Telephone Slamming