Having spent a ton of my own money on FB, I can say it does work in many instances, especially with direct response (like what you were trying). It could easil

Having spent a ton of my own money on FB, I can say it does work in many instances, especially with direct response (like what you were trying). It could easily be targeting too large of a demographic or simply not having ads/landers tailored to your audience. It could simply be a product that is not well suited to selling on Facebook as well, which I've seen plenty of times.