Hi LTOUser,
Thanks for contacting Apple Support Communities!
We understand that your daughter uses a dual SIM, one SIM for the US and the other for Italy but she's still being charged for international roaming.
When you disable Data Roaming on the iPhone, it only prevents the internet from being used and you could still make or receive calls on the US line. You can learn more about cellular data roaming options used on the iPhone here: About cellular data roaming options for your iPhone and iPad - Apple Support
"Turn off Data Roaming or prepare for a trip
Need to avoid roaming charges because you arrived at your destination without an international data plan? Check your Cellular Data options and turn off Data Roaming.
- In the Settings app, tap Cellular, or Cellular Data, or Mobile Data.
- Turn on Cellular Data, then tap Cellular Data Options.
- Turn off Data Roaming.1,2"
She could reset her cellular connection if she turns on Airplane Mode, restarts her iPhone then disable Airplane Mode again and check that Data Roaming is disabled again.
You could also check with Verizon to determine if they can suspend her phone number with them for the duration of her trip as well.
We hope this helps.
Cheers!
