The Sims 3: University Life content isn't in game.

Hi, sorry, I am new to this so I'm not sure if I've done this correctly.

Yesterday I bought The Sims 3: University Life EP in the Steam Summer Sales. As far as I knew, the DLC downlaoded without an issue, but I've been playing the game and none of the University Life content is in it. The mascot doesn't come to my door, there's no items from it in buy mode - it's like it hasn't really added into my game.

I've found this issue elsewhere, but only with Mac users. I'm using Windows 8. I know that The Sims doesn't always work with Windows 8, but all of the other EP's I have bought (Ambitions, Seasons and Generations, I believe) and the base game have worked perfectly.

Again, I'm sorry if I haven't done this correctly - I would really appreciate some help in understanding what I've done wrong or if I can fix it!

Many thanks, Ella.