Likes's are a tricky thing to leverage as a marketing tool (despite it being one of the things marketers use as a metric of Facebook success) If I "Like" a brand and they use it to just start sending me offers and coupons I'm very likely to "unlike" it very quickly. I do this every day.
I'm not sure anyone has really nailed the formula for converting "likes" to actual sales.
Social media is like real world networking, if you go to a networking event and constantly talk about what you're doing, and handout some coupons no one is going to be very interested.
Targeting friend likes would have been a good way to build likes and then with a decent social media strategy where they post things interesting to their audience would have translated into sales. Given the wide range of pizza I'd think a morning show / George Takei format where they post stuff that's entertaining would be a good way to expose people to the brand.
Social media is more about awareness and recall than purchasing intent, similarly to the way McDonalds advertises, they don't expect you to jump off the couch and go buy a hamburger but hope that the next time you're thinking of a hamburger you'll pick McDonalds, or the next time you see a McDonalds you'll think about getting a hamburger.
If they are intent on converting instantly to sales, I would have put out a web-only coupon that's driven by friends of Facebook likes. Going to the coupon link would drive a remarketing list and then the remarketing list would be used to drive potential customers back to the site / Facebook page.
Seeing no increase in sales from a $240 ad spend Facebook only with no follow on is hardly surprising, imagine McDonalds running one TV commercial and then saying TV doesn't work.
I'm not sure anyone has really nailed the formula for converting "likes" to actual sales.