Joker.com does not send UCE ("spam"). When you receive email which you consider as "spam",
this surely won't have it's source at Joker.com. Being mentioned as "sponsoring Registrar"
in the whois output does only mean that the domain in question has been registered through
Joker.com. Operational services such as mailservice are usually provided by an Internet Service Provider,
which has to be referred to in the nameservice entries.
Please first contact the Owner of the domain being misused as spam source - or being subject of spam mails - to prevent from sending SPAM.
Additionally, you may report such domains to Joker.com.
Joker.com will not automatically suspend a domain for a single SPAM report, but this reporting tool will collect reports and identify
domains with more than one independent report. These domains will then be checked for suspension.