Don't expect your broker to run a massive ad campaign. It isn't required. Ads should be tested carefully and slowly. They should be 'blind ads' where the identity of the company is camouflaged. Otherwise, you run the risk of over-exposing your business.
People are naive and think businesses sell as fast as houses.
When you're still on the market six months later, they'll conclude that something's wrong with your business if it still hasn't sold. Better to keep your marketing effort confidential except to strictly qualified prospects. Your broker knows how to do this. When you get an interested and qualified prospect, plan your negotiation strategy carefully. Remember that your goal is to sell, and not to beat the buyer at some negotiation game.