The regulations contain information on the termination of the contract -
The User has the right to terminate the Agreement at any time with immediate effect by submitting an appropriate statement to the Administrator - in the form of a written statement sent to the address of the Administrator's seat, specified in chapter XI paragraph 7 of the Regulations, or in electronic form to the following address: pomoc(_at_)kontakt.int.pl - or by selecting the appropriate option in the Account settings.
You can also try in accordance with the Act of August 29, 1997 on the Protection of Personal Data (consolidated text, Journal of Laws of 2016, item 922, as amended) and the Act of July 18, 2002 on the provision of electronic services ( Journal of Laws of 2016, item 1030, as amended) - refuse to consent to further processing and should close the account.