I traded my old v2 for an Ender 3 about a month ago on FB Marketplace since he wanted to downsize. Within the first week the guy left the printer on overnight after a failed print off his SD card and he says when he woke up the screen was just lit but showing nothing, and from the image he sent that does seem to be the case. He's demanding a trade back and I'm just trying to make sure we both get what we wanted in the first place.

So to be in good faith without just giving into the trade back demand since I've already started working on this printer's centering issues (which he did disclose before all this), I'm looking for a guide that might be at least somewhat beginner friendly for him. At the very least, something that could potentially help him stop assuming that I knew the printer was broken (for the record, if it was somehow broken before I had no knowledge of it as I was using it normally within days before the trade).

Any help in this headache would be greatly appreciated. Heck, even if there's a way to find out when this issue could have been started in case I missed something I shouldn't have missed before the trade.