MVNO, a kind of virtual phone carrier that pays one of the big, established ones—in Phreeli’s case, T-Mobile—to use its infrastructure. The result is something like a cellular prophylactic. The towers are T-Mobile’s, but the contracts with users—and the decisions about what private data to require from them—are Phreeli’s. “You can't control the towers. But what can you do?” he says. “You can separate the personally identifiable information of a person from their activities on the phone system.”

No you can't Nick. Stop lying to your customers, you're borrowing T-Mobile's network, notorious for leaking PID.

Only read this to see if he randomized SIMs and IMEI, but he’s just borrowing T-Mobile’s cheap SIMs.