I think that the first and most thing is that you take it as a guarantee, as it would not be a problem of your own.
Something you could try is also to turn it off and connect it to the charger and see if it turns on the screen, so you discard that it is Hardware.
If so, you could try to enter Download or Recovery mode (with this you could restore your computer)
In case you have information, try turning it on and calculating the time at which it should already be on.
You comment if there is any solution out there before going for the guarantee