What's the meaning of Haiya in Chinese?
The Standard Chinese term would be 哎呀 (āi yā).
However, you might notice others might pronounce it like ài ya. This is simply because no one exclaims in a “standardised” way.
Your interpretation of “Haiya” can also be attributed to the fact that the expression is merely a verbal exclamation which allows the speaker to convey some degree of negativity before starting on his main message. Hence, there isn’t a big difference when someone says “ai ya” and “hai ya”.
The term 哎呀 was probably invented to show that this expression existed throughout society, not the other way round.