Sign in on your phone or computer. Go the support, choose setup and troubleshooting. Scroll to the bottom of the page and select Agent Support. Follow the prompts. If the remote is less than six months old they will replace the remote.
If its truly a Fire Stick remote, Roku will not replace it.
Will purchase a fire stick remote listed not even 6 months! No customer service or support! Roku should close their doors!!!
What exactly is your problem? What you've posted doesn't seem to mention anything.