Bank of Ceylon Breached My Privacy by Sharing Account Details with My Mom—Can I Sue Them?

I need to get this off my chest because I'm furious right now. After university, I've been working a job for about 6 months. I pay all the bills at home and cover half of the groceries, which I thought would be enough to keep my mother satisfied. But today, I discovered that she has been tracking my salary and expenses for the past 6 months without my knowledge.

I never told her my actual salary, and I mostly order things online, so I couldn't figure out how she knew every little detail about my spending. After confronting her and getting into a heated argument, I threatened to stop paying the bills, which finally made her confess.

Turns out, she was getting all my account details directly from the Bank of Ceylon. Apparently, BOC staff will disclose your account information, including deposits and withdrawals, to anyone who phones them with your account number and NIC number. They knew the account was in my name (male) and not hers, but they still gave out all the details. This has been happening for months, and she admitted to doing it multiple times in the past as well.

This feels like a massive breach of privacy and probably illegal. I'm planning to close my accounts with them tomorrow, but I need to know—is it possible to sue them for this?

I don’t want to let this slide. Any advice would be appreciated.