LG G4 problem

I took a LG G4 phone on an upgrade in Aug 2015. This phone is used by my wife and she noticed that the screen sometimes went dim. Beginning of dec 2015 the screen again went dim and stayed that way. She took it for repairs at the Tygervalley branch but was advised that it was beyond repair. The techicians report indicated liquid damage. She was initially charged R171.00 but the money was later returned. My wife is convinced that there is no way it could be due to liquid damage. The phone came on recently but half of the screen is black and unresponsive. I googled LG G4 problems and see that this seems to be a problem with the LG G4 as there is a number of complaints in this regard. <br> The phone is still under warranty and should be replaced as it appears to me that the current problem is a fault with the phone and not due to liquid damage as indicated by the techician.