Issue with high refresh rates

[Viper1617]

For the past year, I have been having issues with my Acer Predator Z301C monitor. I've returned it twice, and both times they determined there was an issue, and claimed to have fixed it, however, the problem was never fixed.

The monitor is a 144hz monitor, with overclocking up to 200. It is also a G-Sync monitor, and I'm using a GTX 1080. I have tried various HDMI, and DisplayPort cables. On most things, however, the monitor struggles to display above 30 FPS, and flickers badly. This mainly happens on anything with lots of darks, or greys (Ex. Spotify, Unity, and dark games.) Even the on screen frame counter drops to 30. It also has an issue, where it leaves a green trail behind fast moving objects, and dark scenes turn green.

Is there anything else I should try at this point, or do I simply retire the monitor? Acer has said they will not replace the monitor, even though it's in warranty. They said they will fix it, but their past two attempts at fixing yielded no results.

Any help would be greatly appreciated.