Notice how you had an IEP? Some students also have a 504. There are already systems in place to handle the issue you are describing. I have had 504 kids responsibly use their phones to do things like monitor insulin. Most students this does not apply to.
What do you think happens when 500 kids call the police station at once?
What do you think happens when the kids start talking on their phone during a lockdown?
Children do not need 24/7 access to phones.
I’m sorry, but if you have not run a lockdown drill, you have absolutely no clue what you are talking about.