phone call. you'll get thru. fight the power.
some places in the US do import 50,000KM stuff from japan all the time. japan seems to take vehicles with 50,000KM off the road, religiously.
great for us JDM culture lovers. but even then, it doesn't mean all of their crap works. too many hands in the apple pie, so to speak.
i don't know your mechanic, but he could have forgotten to add the correct fluid, and bamm. dead tranny. they're supposed to ship dry.
anything toyota is pretty damm bulletproof. so as hamster alluded to, i also wonder why your mechanic won't rebuild what they had in front of them.
i blame no one. cuz you just can't do it. but, i learned to do all car work myself, because bluntly...i trust no one, but myself. and there are a TON of turds who say they're mechanics.

eBay is a conglomerate of b.s...but they DO love the buyer, so spin it on the seller, and you'll be fine.
or open up a fake account. i can see if i can still do that. i have to speak mandarinsneeze to hook it up with ebay.co.med.nz.