I would not do the shop without further clarification. Email the scheduler again, with "CLARIFICATION NEEDED" and reiterate your dilemma, also requesting that if the shop can't be done on Sunday, you need to do it next week after Christmas or have it canceled. Otherwise you might be doing a shop today that you won't get paid for.
I recently had an experience where I followed the instructions to a tee as it was a new shop for me. The client did not agree and said they were asking something else (I printed it out and I'm right). I gave them what the instructions asked for but somewhere they got printed incorrectly. I don't know if I should move on, but I put in a lot of work and report was not accepted.. Instructions said to ask server if they sell souvenirs, which I asked and was told, no but they have them next door. The client wanted (said scheduler) a yes or no answer, nothing else.
Couldn't they have taken the latter part out after discussing it with me.....I know this a very difficult MSC, I used to work with them and stopped, but they had a nice paying job in Vegas so I took it and once again bambazzled.
I did well in Vegas, but still losing 50.00 over this doesn't seem fair.