A licensee, whether acting on behalf of a prospective buyer or not, may not solicit-by personal contact, telephone, mail or advertising-the sale or other disposition of real estate with such frequency as to amount to clear harassment of the owner or other person who controls the sale or disposition of the real estate.
49 Pa. Code § 35.302
The provisions of this §35.302 issued under the Real Estate Licensing and Registration Act (63 P. S. §§ 455.101-455.902).