AT&T Wireless Services latest application upgrade went awry last week, taking down one of the company's key account management systems.
AT&T Wireless was working on an upgrade of its CRM system, but a glitch in the process caused a break.
For much of this week the company's GSM service customers, primarily in Europe, have been unable to make changes to existing plans or to activate new ones, according to spokesman Mark Siegel.
AT&T Wireless Services' TDMA (Time Division Multiple Access) network customer accounts are tracked on a different CRM system and have been unaffected, Siegel said.
"What happens sometimes when you cut over to a new system is that it doesn't perform, on a temporary basis, at optimal levels. Unfortunately, that's what happened here," he said.
"We have made tremendous progress in getting the problem cleared up. Our stores are coming back and systems are lighting up very, very quickly."
Siegel declined to estimate when AT&T Wireless Services' CRM system would be fully operational, but he said it would be "sooner rather than later".
The company's CRM software is used for various account management functions, such as tracking orders and making requested changes to customers' service plans.
Stacy Cowley writes for IDG News Service