If your site has been effected by negative seo... In other words someone has blasted usually a competitor your site with thousands sometimes millions of spam backlink in a effort to get google to think that your website is a spam website and should be taken off the search engine then have no fear this little guide of tips will help recue your website from negative seo doom. Being negative seo'ed is quite easy to spot.. Usually you will see a spike in your back links... on backlink checker tools like ahrefs.com and other tools like the moz.com site explorer. These tools will show you the growth of your backlinks for free... However there are restriction and so you must buy a subscription for more in depth data about your links or other peoples links.
What can you do if your website has been negative seoed? Well you can wait.. Usually the spam links will come from abandoned blogs, forum or other abandoned websites... Eventually because domain names cost and webhosting costs if the person who owns the website where the spam link to your wbesite is on simply leaves and forgets about the website there is a chance that the link will simply disappear as the hosting run out or the domain expires... However sometimes this may not be the case if for example the hosting or domain register is getting money out automatically from the webmasters account... Or it is a free host and domain name.
Because i said before that these are often abandoned websites it doesn't make any sense to fill out the contact form on the website... Instead get in touch to the web host instead using whois data and ask them to do something. After all spam websites on their host is bad for business and for seo for all other websites they host too.
Disavow those links... Find and disavow all links by domain or subdomain! And just hope google takes pitty.
I hope this helped you to run your website better!