Many so-called SEO companies and bogus SEO “experts” offer packages of backlinks. The assumption is that these links will improve SEO, and place your website higher in search engine results.
Google’s policy is very clear. It is against Google Webmaster Guidelines to buy links:
What this means is that Google knows about the websites that your links will appear in. Many of them are called Link Farms, which are worthless websites that exist for no other reason than to provide meaningless links to your website and thousands of others.
If your website is listed on these worthless websites, you are guilty by association of engaging in a scheme intended to artificially boost your search engine ranking. Google monitors these websites, and if it finds links to your website on them, then your website will be down-ranked or removed entirely from Google listings.
Although you may temporarily experience an increase in traffic from using paid links, the axe will eventually fall. Permanent damage to your website will have been done. It is virtually impossible to get harmful backlinks removed.