Is it illegal for another person to access a persons Bank Account via the internet without the person knowing?
If you previously gave her access to your account the fact that you broke up doesn’t change anything, she probably still has legal access. If she didn’t have legal access then yes it is illegal but it since she didn’t withdraw any funds it’s a civil matter, not criminal. You could sue her in court for invasion of privacy but it won’t be worth your trouble. Just close that account and open a new one. Problem solved. I read some of the other responses. She has your account number so just changing your password won’t do it. There are ways of getting in if you know the account number since she also probably knows your social security number and other personal information.