Exhibit 3.399

STATE OF DELAWARE

SECRETARY OF STATE

DIVISION OF CORPORATIONS

FILED 09:00 AM 04/17/2002

020246811 – 3515695

CERTIFICATE OF FORMATION

OF

TIME WARNER CABLE INFORMATION SERVICES (MAINE), LLC

This Certificate of Formation of Time Warner Cable Information Services (Maine), LLC (the “Company”) is being executed by the undersigned for the purpose of forming a limited liability company pursuant to the Delaware Limited Liability Company Act.

1. The name of the Company is Time Warner Cable Information Services (Maine), LLC.

2. The address of the registered office of the Company in the State of Delaware is Corporation Trust Center, 1209 Orange Street, Wilmington, DE 19801. The name of the Company’s registered agent at such address is The Corporation Trust Company.

3. This Certificate of Formation shall be effective at the time of filing with the Delaware Secretary of State.

IN WITNESS WHEREOF, the undersigned, an authorized person of the Company, has executed this Certificate of Formation this 16th day of April, 2002.

/s/ Jill A. Clarke

Jill A. Clarke