The more you SELL,
the less you will sell.
Having a company page on Facebook is great but remember, if people like your page, your posts will show up in their FB feed. So if you are annoying, they'll either UNlike you or HIDE you (HIDING you is worse since you think they are following you).
So you have to be relevant and interesting. Stop selling. Sure, it's ok to post a product or special on occasion but you have to be interesting with it. And post things that are useful to get people thinking. Even if you didn't sell the promotion, talk about current uses of promotional products in big launches and big events. And include snippets to great AND RELEVANT articles and a link to the original article.
The one site you MIGHT get away with being very product focused is PININTEREST. Pininterest is all visual so having cool, cooky and unique promotional products is actually a part of being social. And it transfers well to Facebook.
But, I still prefer, for most distributor and supplier salespeople, to be friends with the person. If that person is interesting. You don't want to be a star, you just want to be interesting enough to have people not be annoyed when they see your posts.