Slamming is the unlawful practice of changing a subscriber's selection of a provider of telephone service without that subscriber's knowledge or permission.
The passage of section 258 of the Telecommunications Act of 1996 significantly expanded the Commission's existing authority to deter and punish slamming. Section 258(a) provides that telecommunications carriers must adhere to certain authorization and verification procedures in submitting and executing carrier changes, to ensure that they have the subscriber’s permission to make the change. Section 258(b) provides that a carrier that violates these procedures and then collects charges from a subscriber shall be liable to the subscriber's properly-authorized carrier for all charges collected.
The Commission’s slamming rules took effect in November 2000; later amendments took effect in 2001. On June 8, 2018, the Commission released an order amending the slamming rules to codify a ban on material misrepresentations on sales calls and unauthorized charges on telephone bills, and to improve the effectiveness of the third-party verification (TPV) process.