However, as with most things that sound too good to be true, it is. Whenever the word ‘guarantee’ is used in relation to SEO services you should stay well away. Search engine rankings can never be guaranteed, and no ethical SEO company would ever offer guaranteed search engine rankings.

Totally agree. SEO can't be guaranteed. But sometimes it's difficult because many potential clients have been conditioned by some SEO expert that results can be guaranteed. It's difficult to compete against that especially if you are new.