The device connects and is responding in the app without issue however when pressing the power icon it makes a click sound but fails to turn power off.

I can give it a small knock on the side and the relay will close and power will switch off. This knock isn't moving the plug so that it loses physical connection to the socket. It is only gentle. 
 

The device is only 3 months old. Should I return it to the retail shop for replacement?

I have read on Reddit and other forum posts with people experiencing similar issues. Is the relay on this device badly engineered?