This exact story is a replica of my last week. Bought a Sims 3 expansion, talked to 2 or 3 different "EA advisors" on chat, all which had to end because they made me restart my computer. I've spent DAYS trying to fix this only to have wasted $30 and much of my personal time. Deleting and reinstalling Origin, Sims 3 and all my expansions twice was really useless.
They made me make a whole new account on my computer, turn off my firewall and antivirus and change handfuls of my computer settings. My computer now runs slower than ever because of the * they made me do to it, which still did not even fix my problem.
I just want my money back and for EA to not have any association with Origin, aka the worst gaming platform of my life. I really wish I had bought The Sims on Steam. Will literally go out of my way to tell people to download elsewhere. Unreal.