With regard to phone records, the relevant precedent was set almost 40 years ago in Smith v. Maryland, which held that the government can subpoena phone records without a warrant. And that case was correctly decided for two different reasons:

1) The "expectation of privacy" must be objectively reasonable. It's objectively true that phone call records are not private: they are kept by the phone company in the ordinary course of business and many people have access to them. As a purely factual matter, a lot more people (people who, unlike the 7-11 clerk, you've never even met!) have access to your data at a phone company than at a 7-11. So any subjective belief that those details are private is not objectively reasonable.

2) Callers have no ownership or control over call records. Even if you don't subscribe to the "property rights" view of the 4th amendment, you have to admit that it's less reasonable to have an expectation of privacy in something someone else owns and controls. It's not reasonable to expect privacy as to a 7-11's recordings of what you do on its premises because they own the recordings and control the premises. Similarly, it's not reasonable to expect privacy as to AT&T's records of what you do on its telephone network.