Md. Code, Business Regulation § 7–103

(a) This title does not prohibit the State Division of Consumer Protection or a local consumer protection unit from enforcing the Maryland Consumer Debt Collection Act or local law.

(b) A local or State unit may not bring an action against a licensed collection agency for a specific violation or complaint for which an action against the licensed collection agency has been brought by:

(1) the Board under this title; or

(2) the State Division of Consumer Protection or a local consumer protection unit under the Maryland Consumer Debt Collection Act or under local law.