Hello,
I just opened a "repair ticket" by Acer customer care about my problem.
But I want also for my knowledge, and may be before they accept that I send my device to them, ask the community 
So my phone works since I bought it (around 3 weeks ago) perfectly.
It's a Acer Liquid E700 tri-sim, which I find simply the best phone I ever had (sadly with some annoying things, but I can definitely live with that !)
Yesterday I still called some friends, and then let my phone lying somewhere in the house with 80% battery, until I wanted to unlock it and look at it.... IMPOSSIBLE !
First I thought it was the battery empty, which didn't sound logical, but I tried to charge it, through normal charger and through my PC. When I do that, the blue LED goes on... but impossible to get the device on ! Even after charging for a night !
I don't know what to do, cause we can't remove the battery and put it back...
The device doesn't get on at all, even in recovery mode, nothing happens at all... (Long press Power button, Long press Power + Volume down, ... I tried almost everything)
I read this is called Sudden death syndrom (SDS) by Samsung products.
Does anybody experience / solved the same problem ?
Or have any idea what I could try?
Thank you !
Bruno