U.S. Cellular and Amdocs have reached a five-year service agreement covering business and operations support systems (B/OSS).

Amdocs will continue handling service activation, customer care and retail interaction, and billing for both business and retail customers.

“This agreement with Amdocs is expected to provide us with improved operating efficiencies as well as enhanced system support capabilities that further enable our goal of delivering a superior customer experience,” U.S. Cellular Vice President of Information Technology John Cregier said in a statement.

The new agreement comes after U.S. Cellular has struggled for years with customer billing mishaps. In 2013 the carrier received numerous complaints regarding its billing system. In 2014, U.S. Cellular Vice President of Sales and Customer Service Jay Ellison apologized for the continued billing problems.

But after today’s new agreement, U.S. Cellular sounds confident the worst is behind it.

“U.S. Cellular has worked hard to get our service levels back to our historically high levels. We have stabilized our billing system, and we are in a strong position to keep growing our customer base with competitive offerings in all aspects of the customer experience—network, devices, plans, pricing, and customer service,” U.S. Cellular spokesperson Katie Frey said in an email.