After all the brouhaha with the Cambridge Analytics dataset, that only revealed data that people voluntarily submitted to a public service - I wonder if there's

After all the brouhaha with the Cambridge Analytics dataset, that only revealed data that people voluntarily submitted to a public service - I wonder if there's a congressional hearing about a service that allows to track anybody owning a cellphone (which is pretty much anybody) anytime, anywhere, with no recourse or opt-out? With heads of AT&T and other companies being interrogated by Congressmen, at least? And if not, why not?