Adding comment from AT&T in response to whether customers will get refunds.

Adding clarification from AT&T that the service disruption is related to a faulty software upgrade.

High-speed Internet, digital TV and digital phone service? Sure sounds like the future. But when all those services blow out like a candle, it will feel as if you’re living in the stone age. Some AT&T customers are learning that the hard way this week.

AT&T’s U-verse service, which includes its phone, Internet and digital TV services, has been down for three days now in some states in the Southwest and Southeast. Mark Siegel, an AT&T spokesman, said less than 1 percent of U-verse’s 7.4 million subscribers were affected by the service disruption, which is related to problems with a software upgrade. He declined to elaborate on what caused the software upgrade to fail.

“AT&T customers in some of our markets are experiencing issues with U-verse service,” he said in a statement. “This issue currently affects less than 1 percent of our U-verse subscribers, but that is too many and we are working hard to fix this. We are making progress in resolving the issue which is related to a software upgrade, and are working to determine when service will be completely restored. We apologize for this inconvenience.”

Wendy Miller, who lives in North Carolina, said in an interview that her U-verse service has been out for three days, and that she has heard nothing from AT&T about what the problem is and when it will be fixed. She said this experience made her miss the old days when the landline would still work even if the power went out.

“You go on U-verse, and the old handy dandy landlines that would work no matter what?” she said. “That’s not happening any longer.” She added that her husband, who works from home, had to move somewhere else with a working Internet connection this week.

Dozens of U-verse customers took their complaints to AT&T’s online forums, in the thread “U-verse outage — what’s going on?” Some talked about switching to another provider, like Comcast, while others said they had to go to a library or a Starbucks just to get on the Internet.

When asked whether AT&T would issue refunds to customers, Mr. Siegel would only offer this statement: “We will take care of our customers.”