I have an unlocked Verizon iPhone 5. I put a Google Project Fi SIM card on it (which uses T-Mobile's network) and I could only make/receive calls and text messages. I would not connect to mobile data, however. I tried the Verizon SIM card of a friend and it worked fine both calls and mobile internet. I read that the iPhone 5 from Verizon would not work in the 3G of T-Mobile, but I still expected to get 4G. Is there any way to fix this?