Some SEO (search engine optimization) companies guarantee that you get a special search engine position if you let them do the work for you. Actually, this is not possible. No company can guarantee search engine listings.
If a company makes such promises, take a closer look at the guarantee. The catch is often that the company selects the search terms. You'll be listed for obscure search terms that nobody searches for. If you have a unique company name or a unique product name, it's relatively easy to get high search engine rankings for that term.
The only way to get high search engine rankings and staying there is good web page content and playing by the rules.