Thank you for your post and welcome to the Bose Community.
I'm really sorry that you're having some problems connecting your NC 700 headphones to your iPhone.
I would recommend clearing the pairing list on the headphones. This can be done by holding the switch in the Bluetooth position for 10 seconds until you hear "Bluetooth device list cleared". Then, on your iPhone, MacBook and any other previously connected device, go to the Bluetooth list and delete any instance of the headphones. Now please try to reconnect.