All emails will be changed automatically which means you will be able to log in on the Windstream website just like you did on Alltel. However, not all emails were changed automatically due to unknown reasons. In this case you will have to take advantage of the Customer Support. Access the official page and then click on the Live chat or Email US at the bottom of the website. Explain the situation and the support technicians will provide necessary information.
Customer Support: http://www.windstream.com/Support/