Prevent mobile data being turned off

Does anyone know how to prevent mobile data being turned off on an iPhone 6 and iPhone 7. I want to ensure my daughters data is not able to be turned off at any time.

their other parent turns off the data when they are in their care therefore not allowing me to speak to my daughter even though I bought the phone.

I want to find a way to stop them being able to turn off the mobile data

Solution 1:

Go to Settings > General > Restrictions

If you have setup Restrictions, enter your Restrictions passcode. 

If you have not set it up yet, enter a password (twice) and enable Restrictions.

Make sure you will never forget this passcode; it is required even when resetting the phone. If you forget it, not only will you be disallowed from entering the Restrictions section, you will also not be able to reset your iPhone.

On Restrictions page, go down to the “Allow Changes” section and click on “Mobile Data”.

Set “Mobile Data” to “Don’t Allow Changes”. 

Leave the “Data Plan” to “Allow Changes”.

Open control center once and close it.

For iOS 12 here are the instructions