Section 8. The commissioner may suspend or revoke a license issued pursuant to this chapter if he finds that:

(a) the licensee has violated a provision of this chapter or any rule or regulation adopted hereunder or any other law applicable to the conduct of its business; or

(b) a fact or condition exists which, if it had existed at the time of the original application for such license, would have warranted said commissioner in refusing to issue such license.

Except as provided in subsection (a) of section nine, no license shall be revoked or suspended except after notice and hearing pursuant to chapter thirty A.

A licensee may surrender a license by delivering to the commissioner written notice that it hereby surrenders such license, but such surrender shall not affect the civil or criminal liability of such licensee for acts committed before such surrender.

No revocation, suspension or surrender of a license shall impair or affect the obligation of any preexisting lawful contract between the licensee and any person.

In lieu of suspension or revocation of a license issued hereunder, the commissioner may fine a licensee up to a maximum of five hundred dollars per day for each violation.

The commissioner may suspend or revoke, or impose a fine on, only the particular license or licenses for particular places of business or locations with respect to which grounds for revocation occur or exist; provided, however, that if said commissioner shall find that such grounds for revocation are of general application to all places of business or locations of the licensee or that such grounds for fine, suspension or revocation have occurred or exist with respect to a substantial number of places of business or locations of such licensee, said commissioner may suspend, revoke or impose fines with respect to all of the licenses issued to such licensee.