Re: Got EA Play membership but Late Night pack for Sims 3 isn't installing.
@maddew123 Please click on the Sims 3 icon in your Origin game library, then select More > Expansion Packs, and scroll down to Late Night. You may have two or even three LN entries in the list; look for a Download button on each one, and if you see one, click it. If the pack says Installed already, please let me know.
I'm guessing you mean that the launcher's Expansions & Stuff tab doesn't list Late Night. Does it list High-End Loft Stuff? You get that pack with an EA Play subscription too; please install it and see whether it shows up.