Can i throttle the data and/or turn it off on my second phone
Your only option would be family base, which is $5 a month. I think you might need to device though in order to activate it. The only other option is to suspend the line, then it won't work at all. You can suspend with billing so that it doesn't extend the contact, or suspend without billing which will extend a 2 year contract.
You can turn the data off on the actual device. Though it can just be turned back on. What device is it?
You can also pay for family base which allows you to limit the amount of data devices use.
I'm sorry my ? wasn't clear. My ex has my 2nd phone and she is running the data through the roof.
Even though both my phones are in my name? I can't suspend the line she has my daughter and I agreed I would not do that