Can not verify FIOS account on Verizon Up app

I cannot change the FIOS username field in the verify FIOS account page on Verizon Up app to take advantage of the FIOS + mobile accounts rewards/discount program. It is pre-filled with my Verizon mobile username which is different from my FIOS username. When I attempt to make one of them the same as the other in the profile settings, it says that the username is already taken.

Re: Can not verify FIOS account on Verizon Up app
Moderator Emeritus

Hi rhdcheme1,

Your issue has been escalated to a Verizon agent. Please check your Private Messenger Inbox for a message from a Verizon Support agent. You can find your Inbox by clicking on your username at the top right corner of this page and then clicking the envelope icon that appears at the top of the menu. Response times may vary and may be delayed at this time. Please continue to check your Inbox for a reply from a Verizon agent. Please direct all correspondence concerning your issue to the agents who will be assisting you privately.