AT&T announced Sunday that it would give $5 in bill credit to thousands of customers affected by last week’s widespread cellphone service outage.

The outage on Thursday affected more than 70,000 customers at its peak but included waves earlier in the day, when outages for more than 32,000 and 50,000 customers were reported.

“We apologize for Thursday’s network outage,” said AT&T, based in Dallas. “We recognize the frustration this outage has caused and know we let many of our customers down.”

The company said in a statement the day of the outage that an initial review found the lack of service was “caused by the application and execution of an incorrect process used as we were expanding our network, not a cyber attack.”

The outage drew an investigation from the Federal Communications Commission, with the FBI and the Department of Homeland Security lending a hand, White House officials said.

AT&T said the $5 credit could take two bill cycles to take effect, and it added that the reduction won’t apply to prepaid, business and Cricket Wireless customers.

“For the portion of consumer and small business customers most impacted by the outage, we are automatically applying an account credit,” it said.

The company said it was also working to ensure such an outage isn’t repeated.