Some former Alltel subscribers in South Dakota have been told their service might be limited because of the transition to AT&T. AT&T bought Alltel’s customer base when it acquired former Alltel assets from Verizon in June. But customers in remote areas who had relied on roaming off Verizon towers will no longer have that capability. A state Public Utilities Commission spokesman says the news is surprising because the commission was told the coverage would be the same or better. AT&T would not tell the commission how many people are affected. An AT&T spokesman says the company only recently learned that some areas will not have coverage. Former Alltel customers will have 30 days after AT&T service starts to decide whether they want to keep it.