I think they simply use whatever cable is cheap and available. No one sees it unless they cut it open.
The danger would be cutting it at the appliance end and making assumptions.
The colours are irrelevant in this case. It is what pins the colours were connected to which is relevant. That decides what they were. Anything else is hypothesis.
^ My point was. They hang up because "they" cannot speak, or are not confident in, English. This is Thailand so most business is conducted in the local language.