Search engine marketing services don’t generally guarantee results.
They do keyword research. They know what people are searching for, how they are searching for it, and when they are searching for it. They know who offers these products and services aside from you, so they can tell you who your competition is. They know which search engines you should advertise on. They know which keywords you should use. Despite all of their knowledge, search engine marketing services don’t generally guarantee results. They will do their best to generate traffic to your website, but they cannot guarantee that their efforts will be productive.