It's time consuming to become a master of manipulation. I get that. On top of that you're trying to grow your business. One of your tactics, you're told, should be harnessing the power of your website through search engine optimization.
"Search engine optimization" as defined by Wikipedia:
Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's unpaid results—often referred to as "natural," "organic," or "earned" results. In general, the earlier (or higher ranked on the search results page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine's users.
But you find the tubes and gears and pulleys of the interwebs overwhelming. So you decide to outsource this task to people who know it better than you. This makes perfect sense.
What do you really know about these people who promise you high search ranking for your money? Does it matter?
Yes. Yes it does matter.
When you hand over the promotion of your internet identity to the lowest bidder, some interesting things can and do happen. The people doing the work may be located in a different country and may not have a great handle on the English language. The people doing the work may use the strategy of comment spamming any semi-related website they can find.
Why should this matter to you?
How do you think it reflects on you if the people who are promoting you uses spammy language? It's a red flag for many people, who view paid comments as meaningless. (If you're a believer that any publicity is good publicity, then maybe it doesn't matter.)
As for comment spamming to impact SEO, not only does it not work, it can work against you. It doesn't work for one or more of the following reasons: a) the comment section of many websites are coded so as to not pass on "Google juice," b) comments are sometimes left on untended sites which don't have high PageRank, and c) when comments are left on actively managed sites like this one, the spam comments are deleted within 24 hours (you've paid good money for something that gets permanently deleted in less than a day!!).
Worse than that, some SEO organizations will target blogs of potential clients, and leave comment spam representing themselves as you and your brand. These can hurt both you and your SEO in the long term.
When I get those types of spam comments, it's annoying to be sure -- and I remember who you are because you're wasting your money and my time every time I have to cleanup the spammy mess you paid for. However, when potential clients get those kinds of spammy comments, they often black list you and share your name around with all of their contacts as people to avoid. It happens. I've seen it. It's not pretty.
What should you be doing?
You know your business best. You know your budget. I can only suggest to you that you do a quick search for "things you should ask before hiring seo company," and that you remember you pay for what you get.