D.C. Mun. Regs. tit. 26, r. 26-A308
If the insured disputes the validity under this chapter of a purported cancellation or nonrenewal, he or she may at any time before the effective date of the cancellation, or in the case of nonrenewal, the end of the policy period, send written notification to the Commissioner of the reasons why the insured believes the purported cancellation or nonrenewal is invalid. The insured shall, at the same time, send the insurer a copy of that notification.
The Commissioner shall, unless the matter has been settled, proceed to determine whether the cancellation or nonrenewal was authorized under the terms of this chapter.
Decisions of the Commissioner shall be appealable under the applicable provisions of the D.C. Code.
D.C. Mun. Regs. tit. 26, r. 26-A308