It would be good to know if the SEO company you hire knows the fine line between ethical and unethical SEO methods or practices. If they employ illegal methods on your site, then the chances are, you could get banned from most search engines, and see your online business fail.
You can read easily Cloaking is a search engine optimization (SEO) technique in which the content presented to the search engine spider is different from that presented to the user's browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page.
Cloaking is one of the worst things you can do to your website. It is strictly prohibited by Google and if you caught up playing these kinds of tricks with them then your website could be taken down and this is one thing that you certainly won't want to happen.
Cloaking refers to the practice of presenting different content or URLs to human users and search engines. Cloaking is considered a violation of Google’s Webmaster Guidelines because it provides our users with different results than they expected.
A website that uses cloaking recognizes search engine spiders by their IP address. It returns web pages to search engine spiders that are different from the web pages that web surfers see. Usually, the cloaking software creates hundreds of web pages that are optimized for a special search term so that search engine spiders get the impression that the website contains a lot of relevant information about a special topic.
If you often search on Google then you probably can confirm that you can get good results with cloaking. You can often find web pages on Google that have little to do with the description on the result page.
Most search engines will immediately remove and sometimes blacklist a site that is discovered to be cloaking. They do this because cloaking is usually intended to completely fool the search engine's algorithms and programming that determine what makes a site rank high or low in that engine.