iOS 10 broke cellular data

My daughter has an iPhone 5c that she's had for about two years and it's worked great. She updated it to iOS 10 and the cellular data has not worked since. I've had Verizon tech support check the account, and two different Verizon stores have changed the SIM card with no luck. They say it's an Apple issue. The weird thing is, if I swap the SIM from my iPhone 6 into the 5c, it works perfectly. Hasn't worked with it's original SIM or either of the two new Verizon SIMs.

I've reset the network settings over and over. Cellular data doesn't work on LTE or if limited to 3G. I've even gone as far as doing a DFU restore on it for new firmware and software and set it up as a new iPhone, just in case it was a software issue. I'm going to take it to the Genius Bar at my local Apple Store, but it'll be a couple of days before I have time to do that... so any ideas on how to fix this? I've tried every solution I can think of or even random ones I find on the net. Nothing has worked so far. The only error message I get is "Could not activate cellular network" when the phone tries to connect and fails. Texts and phone calls work fine, and wifi has no issues either. Just no cellular data at all.

Thanks!