You are not being clear. Did you purchase the Sims 2 Collection from Origin? If so, Origin should have that record. If you used the word "download" incorrectly, it does not mean the same thing as the word "install". If you bought the hard copy on disk and want to install it once again, you will have to verify that you formally REGISTERED with the Serial Number on the Simcity website.
In that case, a Game Adviser should be able to locate the code in your record, but there are none of those here at AHQ, which is gamers discussing games with other game players. If you need to visit in AHQ about the Sims 2 in the future, please use the dedicated forum, ot "Other Games".
https://help.ea.com/contactus