The Secretary of the Interior may prescribe rules and regulations governing the recognition of agents, attorneys, or other persons representing claimants before his department, and may require of such persons, agents, and attorneys, before being recognized as representatives of claimants, that they shall show that they are of good moral character and in good repute, possessed of the necessary qualifications to enable them to render such claimants valuable service, and otherwise competent to advise and assist such claimants in the presentation of their claims and such Secretary may, after notice and opportunity for a hearing, suspend or exclude from further practice before his department any such person, agent, or attorney shown to be incompetent, disreputable, or who refuses to comply with the said rules and regulations, or who shall with intent to defraud in any manner, deceive, mislead, or threaten any claimant, or prospective claimant, by word, circular, letter, or by advertisement.