Borrow Your Friends Remote
You can use your friends remote for controlling your own fire tv stick. Pretty much all fire tv stick remotes work with each other. All you need to do is, pair them once. To do that, you need to do is:
Push menu, back, left circle button together for about ten seconds and then reboot your fire tv stick. This will connect your fire tv remote with the fire tv stick.
How to Connect Fire TV Stick to Wifi Without Remote-Use Your TV Remote in Replacement of Fire TV Remote
Install the app in your phone and you can use it as the HDMI CEC and use your tv remote as fire tv stick remote replacement. This would let you control your fire tv stick. Also do call the firestick technicians.