Perhaps it came with an expansion that you might had brought on Origin as they had some that included a store set as a bonus since the CYS isn't available with that set.
I once had this happen with the chocolate fountain. I was in my game playing Lucky Palms as I had jusr gotten the world and noticed the chocolate fountain was available for me to use. The thing is, I never brought the fountain and it was never in my purchase history as being owned. So even though it was in my game, I went and spent the simpoints for it so that it does show in my purchase history.
Edit to add this link from Carl's Guide that has a list of EP's that had added some store content to was to be sold for a limited time. The set you have came with the Ambitions EP if you had brought it back in 2014 before the promotion was over with... :)
http://www.carls-sims-4-guide.com/forum/index.php?topic=19796.0
