Has Standard Bank been hacked or why do I get a Tax certificate with no bank account?

I received a Tax certificate from Standard Bank addressed to me, with Full Initials and surname, even though I do not have an account with them. I could not open the encrypted (PDF) attachment with my ID. My Wife has an account, also received one addressed to her, and could also not open it. I went to the bank who looked up my details but confirmed I do not have an account. What concerns me is according to the POPI act they should not have my details, and I now question if they have been hacked for someone to get to my details, or is it a flaw in their system, or do I have money at Standard bank which has tax implications for me if a certificate was issued? Why did my wife also get the same email with a tax certificate which she also could not open? Has our details been leaked by teh bank to a third party and why does Standard bank still have my information on their system after my account was closed years ago? The header emails on the email indicated it was send from a private computer (IP 127.0.0.1) running a mail server. The lady at the bank said she was swamped and I should just delete the email and ignore it???!! Seriously?