If the candidate does not comply with those guidelines, Google may completely find a restriction on the search results if your website is degraded to find a lot less or engine rankings. Do they guarantee good results?
Any SEO Agency cannot guarantee the first position or any status of search engine SEO algorithms and strategies repeatedly changing a few weeks and the need to update it to the SEO companies. While you are an example of what you’ve achieved for our other customers, but it’s not sure that you’ll find the same situation. If an agency guarantees results, then search for another company.