Surely we are close to the point a fully self-service cell account is possible via secure portal? Choose to eliminate human customer service, expose portal to user with appropriate MFA access controls etc.

I guess what I'm asking for is a cellphone plan with no human customer service, similar to how there is basically no one I can call if I have a problem with a gmail account. Remove the source and the temptation of this attack in one go.

I appreciate not every customer would like or want this, but could be offered to more security conscious users as an option. It's not unheard of to get a discount for pre-paying or enabling auto-payments on cell plans around the world, perhaps you could even get a few bucks off a month for choosing to not have option to call a contact center too.