The company thats in charge of SunRockets assets is suing Vonage.
Sherwood Partners, a company that handles tech firm liquidations, says Vonage illegally obtained, and is using, SunRockets customer list.
SunRocket was the second-largest consumer VoIP provider; it went belly-up in July.
Vonage says it got the list fairly, though a third-party marketing company in New York.
Virginia-based SunRocket closed its doors with no notice in mid-July. Media reports indicate SunRocket and Vonage were negotiating the sale of SunRockets customer list before that provider suddenly shut down.