D.C. Mun. Regs. tit. 16, r. 16-650
A licensee shall not make or authorize any written or oral statement which is untrue or misleading; or any oral or written statement which is known to be untrue or misleading, or which by the exercise of reasonable diligence should be known to be untrue or misleading.
Advertising deemed to be misleading or untrue shall include, but not be limited to, advertising which fails to conform to the requirements of § 651.
A licensee shall not fail or refuse to give the customer a copy of the final bill or any document requiring the customer's signature, as soon as the customer signs the document.
A licensee shall not commit any act related to the operation of consumer repair services involving dishonesty, fraud, or deceit.
A licensee shall not follow any course of conduct which constitutes gross negligence.
A licensee shall not make false promises of a character likely to influence, persuade, or induce a customer to authorize the repair, service, or maintenance of consumer goods.
A licensee shall not aid or abet an associate, employer, or partner in the commission of any of the acts prohibited under this chapter.
A licensee shall not condone or affirm the commission by an employee of any act prohibited by this chapter.
A licensee shall not exhibit a persistent pattern of conduct which departs from or disregards accepted trade standards.
A licensee shall not fail in any material respect to comply with the applicable provisions of this chapter or the rules adopted pursuant to this chapter.
D.C. Mun. Regs. tit. 16, r. 16-650