There are several posts like these:
How does one protect themselves against an attack like this?
What are the specific logistics behind services or phones or technologies that can be used to create a structure which isn't vulnerable to this? And how does the data flow through it?
Also, how do high risk people like celebrities handle stuff like this?
These are the things that are most critical to protect
- Cellular account if used for any SMS (but maybe it can be avoided entirely by only using email recovery?)
- A "root" email account that is for recovery
- Domain accounts (eNome, namecheap, etc)