Hi,
What kind of spam are you talking about ?
If it's spam going to your email address with no link to your website, there is not much you can do on your website besides not publishing the email address, but that's already too late now. Your mail client might have anti spam tools you can configure.
If you're talking about your server sending spam emails because your website got hacked, you need to check with security specialists. For example, sucuri are specialists in that domain:
sucuri.net/guides/how-to-clean-joomla/
If you're talking about getting fake registration on your website, there are a couple of things you can do on your website:
www.joomlashack.com/blog/joomla/how-to-p...-spam-using-captcha/
(note that instead of Joomla's ReCaptcha plugin, you should instead use the ReCaptcha we provide as it's compatible with HikaShop's registration form too).
