DALLAS—A teenager and a 23-year-old man from Massachusetts are headed to prison after being sentenced in Dallas on conspiracy charges related to a phone hacking case.

Nineteen-year-old Matthew Weigman of Revere, Mass., was sentenced to more than 11 years in prison Friday after pleading guilty to one count of conspiracy to retaliate against a witness, victim or an informant and one count of conspiracy to commit access device fraud. Twenty-three-year-old Sean Paul Benton of Malden, Mass., received an 18-month sentence after pleading guilty to one count of conspiring to obstruct justice.

Prosecutors say Weigman hacked into Verizon computers to obtain identifying information on customers and change or discontinue their service. He and Benton then harassed a Verizon investigator who was cooperating with authorities in the case.