"No expectation of privacy"

The Federal government is trying to claim that it has the right to find out where we've been, based on cellphone information. The theory is that because the cellular company has to know where we are, that we have no expectation of privacy and the government should be able to know as well. In a word, no. I entered into a contract with the company with the expectation that they would keep my information private; furthermore, the government is restrained, in ways that a company would not be, by the Fourth Amendment. It's a little thing called the Constitution--ever heard of it?