Am I allowed to buy a Verizon phone through someone other than Verizon?

Episode 932 (2:12:12)

Duval from Charlotte, NC

He can buy a phone from someplace else, but he would still run the risk of losing his unlimited plan. Leo says there's no way to really 'trick' them, because no matter where he buys the phone, it has to be activated through Verizon. They don't have SIM cards that can just be put into another phone.

If he buys a phone without the subsidy, he may be able to keep the unlimited data, however.