Voice over Internet Protocol (VoIP) service provider, SunRocket Inc., has shut down its operations Monday without formally notifying its more than 200,000 subscribers.

The company gave no warning on its website that it was shutting down its operations and if a caller tries to reach its customer service line, a brief recorded message, saying: “We are no longer taking customer service or sales calls. Goodbye.” is being heard.

SunRocket Inc. was established in 2004 and was backed by the top-name Silicon Valley venture capital firms Blue Run Ventures, Doll Capital Management and the Mayfield Fund.