Just got my new Quadzilla installed today, should have done it some time ago.
Just one thing I did not see mentioned in the instructions for the IQuad or anywhere else.
On the IPhone you should change the wifi settings for the IQuad.
It should be set to manual instead of automatic in the Configure IP setting
Set the IP Address to (in my case) 22.214.171.124
the Subnet Mask to 255.255.255.0
and leave the router blank
This will allow the Iphone to connect to the Quadzilla and maintain LTE connection for interrnet.