Md. Code, Health Occupations § 1-305

(a) If a referring health care practitioner, a health care entity, or other person furnishing health care services collects any amount of money that was billed in violation of § 1-302(b) of this subtitle and the referring health care practitioner, health care entity, or other person knew or should have known of the violation, the referring health care practitioner, health care entity, or other person is jointly and severally liable to the payor for any amounts collected.

(b) If a claim, bill, or other demand or request for payment for health care services is denied under § 19-712.4 of the Health - General Article or § 15-110 of the Insurance Article, the referring health care practitioner, health care entity, or other person furnishing the health care services may not submit a claim, bill, or other demand or request for payment to the person who received the health care services.