Default HOX+ liquid damage ? ? ?

My sons handset has developed a fault.
Please bare with me..... On the very odd occasion it will boot, it will eventually shut down and won't reboot for hours if not days. If it does reboot it looses the rom and I've got to reflash it. Sometimes it will keep running, but asleep, for a few hours but when it's used it will crash and not restart, as I said above, for hours or days.

The only roms that I can get to run are the "pure" android roms. I can't get any sense 5 ones to start.

I sent it back to o2, but they just sent it back to me stating it's "liquid damaged".

As far as I'm aware it hasn't been "liquid damaged", but obviously can't prove that. I also don't think they've checked it to come to that conclusion. These things are well made and there's no obvious signs of it being taken apart.

Any suggestions as to... (a) Do the symptoms re losing the rom etc, sound like liquid damage ?
(b) Can liquid damage be repaired ?

Personally, I don't think they've done "jack ****" about the fault because it's easier to say "liquid damage" and wipe there hands of it.

Thanks for "listening".