Good point.
Good point.
I agree with @NewtoHK11 it was probably an excuse, they don't have to declare a reason do they? anyway, I sincerely doubt you'll find the reason.
I have had to do this to a candidate. After the hiring process was initiated, the person received, at the 11th hour, some highly negative comments from others in the industry such that proceeding with the hire was impossible.
Our and our lawyers' conclusion was that the person was legally due a week's pay, the same as if s/he had been terminated during the first month of probation.
Not sure on what basis HKG's wife could claim discrimination, but my guess would be it's a long shot. Both parties' (i.e. employee and employer) rights during probation are pretty clear: barring an illegality like discrimination, either side can walk away with or without a reason.
We looked at the probation thing as the worst case scenario: clearly Mrs HKG's would-be employer has decided not even to pay that, which makes it suck even worse.
I have now taken the opportunity to read all of the comments. Your situation is sh1tty and unfair but this is HK, and presumably you will understand that non-locals are treated very differently than to local employees. My advice is this, pursue the bank for the reasons why you failed the background check, but do not go back there, look elsewhere and consider this some form of divine intervention for you not to take up employment there. If its the same place as I am thinking of then it is probably for the best.
Hope this find you well @HKG_2018,
may I ask what agency you are asking for to initiate a self background check full report?