(a) This section does not:
(1) apply to an agreement to share compensation among license holders; or
(2) limit a cause of action among brokers for interference with business relationships.
(b) A person may not maintain an action to collect compensation for an act as a broker or sales agent that is performed in this state unless the person alleges and proves that the person was:
(1) a license holder at the time the act was commenced; or
(2) an attorney licensed in any state.
(c) A person may not maintain an action in this state to recover a commission for the sale or purchase of real estate unless the promise or agreement on which the action is based, or a memorandum, is in writing and signed by the party against whom the action is brought or by a person authorized by that party to sign the document.
(d) A license holder who fails to advise a buyer as provided by Section 1101.555 may not receive payment of or recover any commission agreed to be paid on the sale.