if the devices were removed from your alexa account, they would not work. do you have alexa installed on another device? also check your account on your computer at alexa.amazon.com
try restarting your phone. also try signing out of alexa, then sign back in on your phone. I am assuming alexa app on the iphone is similar so to sign out by opening the app, go to settings, then scroll to the very bottom of the screen.