The Director may revoke a certificate or suspend a license in case of any: Failure to operate the taxicabs in such a manner as to serve the public adequately; Failure to maintain the taxicabs in good order and repair; Failure to maintain insurance as required by this Subtitle; Failure to report any accident as required by this Subtitle; Failure to pay any fees or fines lawfully assessed under this Subtitle; Repeated and persistent violations by the licensee or certificate holder of the Prince George's County Code, including failure to maintain a copy of a duly authorized certificate in the vehicle to which it has been assigned, repeated and persistent violations of the motor vehicle laws of Maryland or surrounding jurisdictions, or a traffic record which indicates an unsafe driving pattern; Suspension or revocation of a licensee's driver's license issued by a State, the District of Columbia, or a United States territory; Failure of the licensee to maintain the trip manifest in good order as required by Section 20-119; Conviction of the licensee or certificate holder of any criminal offense or a conviction or a plea of nolo contendere for any traffic offense involving the use of alcohol or a controlled dangerous substance; Procuring or attempting to procure a license or certificate by fraud, misrepresentation, false or misleading statements, or omission of material facts on an application for a license or certificate; Repeated, persistent, and/or unresolved customer complaints of poor quality service: Complaints will be investigated by the Director; The Director shall require a corrective action plan be developed within thirty (30) days of investigation; The Director shall suspend the license or certificate if not resolved within sixty (60) days; and The Director shall revoke the license or certificate for continued noncompliance; If the applicant has repeated complaints for late response and failure to report to the consumer a reasonable excuse for the lateness; Failure to provide proof of good standing with the State during the annual renewal process; or Any other violation of this Subtitle by the licensee or certificate holder. Where the holder of a certificate is a corporation, the certificate may be suspended or revoked by the Director if the person convicted of any criminal offense remains for more than a period of one (1) month from the time of such conviction as an officer in the corporation or is a stockholder with more than twenty-five percent (25%) of the stock in the corporation. The decision of the Director on a denial, suspension, or revocation is final if it is not appealed pursuant to Section 20-106 of this Code. The violation notice or the denial, suspension or revocation of a license or certificate under this subsection shall be served on the party by personal delivery or by registered or certified mail to the last known address.