The obligations of the service provider and the rules of the protection of personal data of natural persons using the services provided by electronic means are determined by the Act of 18 July 2002 on Providing Services by Electronic Means (Journal of Laws No. 144, item 1204 with later amendments).
According to Article 10 paragraph 1 of the Act sending unsolicited commercial information addressed to the specified recipient by electronic communication means, in particular by e-mail, is prohibited. Commercial information shall be considered solicited if the recipient has expressed his/hers consent to receive such information and, in particular, made his/hers electronic address available for such purpose. Sending unsolicited commercial information shall be considered as unfair competition practice, within the meaning of provisions of the Act of 16 April 1993 on Fighting Unfair Competition (unified text: Journal of Laws of 2003, No. 153, item 1503 with later amendments). Therefore you can turn for help to the Office of Competition and Consumer Protection (www.uokik.gov.pl).
According to the Article 24 of the Act on Providing Services by Electronic Means the transmission of unsolicited commercial information shall be prosecuted on the request of the harmed party.
Article 27 of the Act of 24 August 2001 The Code of Petty Offence Proceedings states that the harmed party can operate as auxiliary prosecutor and lay an action against the responsible party to the court.