[esseye]

I don't know if you understand the scope and intent of their authority if you're implying this is not clearly inside of it. They exist to make sure that people retain reasonable access to communications. That includes stepping in when government agencies would seek to limit them in a way which harms the people. This is a clear instance of just that. There is absolutely no way you can conclude the rates are reasonable/justified. At $2+/minute, they could maintain an arsenal of prepaid cellphones with unlimited time.

They've used this authority for a very long time, and the most basic instances of this are municipalities trying to enact regulations that prohibit people from putting up antennas required for otherwise lawful radio communications.

It is still the responsibility of the prison to maintain and provide access to the phones as long as inmates are guaranteed that right. There's no question of who's accountable there. The prison and department of justice/corrections/etc depending on what type of facility.