The Sims 4 is using up all of my bandwidth

GabrielleAlicia​  I'm not sure either, but you can try blocking everything EA-related in the Windows firewall, or a third-party program if you use one.  This is separate from your antivirus.  You may find several distinct entries, so try them separately and together.

I'm not in front of a Windows PC at the moment and so can't give a better description, but if you need me to, I can look again later today and see what looks suspicious.