Downloading and expansion pack off Amazon

So I bought the downloadable Roaring Heights expansion pack. On my mac laptop already, I have five other expansion packs, all of which were downloaded by disk. 

Here is what I did

1. went to amazon and purchased

2. clicked download

3. was brought to store.thesims3.com

4. made an account

5. went to my page > my account > account details > reedem a code > entered my code

6. went to purchase history > clicked "download"

** then my sims 3 app on my computer popped up and it looked exactly the same and then asked me to put in my Island Paradise expansion pack disk in

I arrived to the home page and my screen said I did not insert the disc so I tried and tried but it still wouldn't take

Then I looked at the bottom of the opening page, after you open sims and right before you hit the big play button, and all of the expansion pack icons that I had were lit up and I noticed that there wasn't a little circle/logo for Roaring Heights ??

Does my computer just not recognize that I downloaded Roaring Heights offline??