How are you trying to get amazon prime?
amazon prime must first be downloaded as an app. Do you have a Roku?Chromcast?Apple TV 4th. Generation? A smart tv?
You need one one to get the app. You then need to get a Amazon prime account.
verizon Fios is not responsible for setting up another companies service.
https://www.amazon.com/gp/help/customer/display.html?nodeId=201422730