Please ensure that you have new batteries inserted in your remote.
If this does not fix your issue, we can test the remote using the following instructions:
1) If you have access to a digital camera that has a screen, or a phone that has a camera feature, turn it on and then direct the remote at the camera lens.
This will determine whether the fault is with the remote or the receiver.
Note: On your iPhone, please use the front-facing camera, as the rear camera will not show the light.
2) While looking through the camera, try pressing any of the buttons you are having issues with and check if a flash of light appears.
The flash will not be the green light from the LED on the top of the remote that lights up when you press buttons, but will be a flash of light that appears at the end of the remote.
It is not visible to the naked eye and can only be seen through the phone/camera display.
If the remote button is working correctly, there will be a flash of light visible through your phone's screen.
If it is not working, there will be no flash of light.
If you see a flash of light but it's not responding or it's sending the same command, check to make sure none of the remote buttons are stuck.