If you have a contract with another party that is not performing to the letter of the contract you can seek a remedy through the Courts seeking redress, you speak here of AIB but it does not matter who you have your contract with or why.
Banks stopped caring about their brand and reputation a long time ago.
The issue in Ireland is that we cannot take a class action suit against large companies, that makes it harder for the small guy to get redress without fear of massive legal bills.
That said if you are right you will win, check your contract, prove you have suffered financial loss and get yourself good legal advice before you go chasing shadows.
Staff are employees, your final point is somewhat unfair.