LG service seriously flawed

Since the beginning I encounter image problems that jumps from time to time accompanied by a sound "click" in Display Port, HDMI ever.
I was persuadué it was from my graphics card, my cables, drivers, or even Windows. Having multiple graphics cards, Ables and others I've tested all possible configurations, and still this problem. I had resigned myself, not thinking that it could come only from the screen but my pc (again, no problems with the HDMI PS4 for example). But falling on a comment here and reading forums, I see that this is a known problem!
My purchase dated September 2014 (we are in March 2015), I contact LG offering me a kidnapping onsite (time of withdrawal: from 8 am to 18h, practical!) For a return within 15 days at best. 15 days (at best) without display for work, you can imagine. And we're talking about an ultra-known problem, not only in France. An on-site exchange is the least of it. But no, LG offers only repair, for a screen at this price it sucks completely.