I don't know how you have so much trouble.
I just received a batch of parts for a 43 yo old motorcycle. All the parts are correct. Source countries: Netherlands, England, Australia and USA.
All engine parts, some are OEM, some are aftermarket. Last night, ordered parts to rebuild and tune the twin carbs along with a detailed "How To" manual. Today, received shipping confirmation. All will arrive in my hands by Monday.
Maybe your cut/copy/paste is error ridden or your parts list is not for your model.
The few parts I ordered from directly Toyota was done at the parts counter looking at the diagrams with the parts clerk. Never an error. I can only figure the common factor is not with the parts source but with the customer ordering what they think is correct. Then pitching a major b1tch when the parts are consistently wrong or looooooonnnnnnnggggg delays.