Apple earlier denied it rejected the program, and said Friday that the two Silicon Valley companies are still discussing the application.
Google Voice lets people pick a new phone number, then route incoming calls to cell, office or home phones. It also lets users place calls from within the application.
Google says Phil Schiller of Apple told Google's Alan Eustace, a senior vice president, during a July phone call that Apple rejected the program.
That's according to an updated letter from Google posted on the Federal Communications Commission's Web site. A previous version redacted the specifics.