If I were you, I would show up to the job. Footprint is a Merchandising company. They don't have work in my area but if they did I would try to sign up. They usually pay according to your experience, if you can convince them. But, how are you going to get experience if you don't go. And, as you gain experience with that company, they will know based on your progressively great paperwork. That's when you hit 'em up for a raise.
The problem is, if you've already signed up, if you bag on them you may not be able to get a job from them for a long time. Some companies, like Apollo and Crossmark, can hold a grudge for a pretty long time (their schedulers / coordinators anyway). Even if the problem was on their end.
Just be sure to tell them that you are "not experienced in all aspects of merchandising" when you show up. Sometimes I'm assigned and I don't know exactly what it is. Sometimes I'm assigned and I have all the facts ahead of time, planogram in hand, the scope of work written out, and then I get there and it's a different animal. I just roll with the punches unless there's temps who are drunk or smoking da kine, then I don't roll so well.