Change of address without my concern

On the 18th September 2017 went for a statement in the branch. The statement was printed only to find that the address has changed. When consulting the enquiry desk as I wanted to correct the address; the gentleman (he had no name tag) asked a proof of address and an ID I gave him both ( I had them because I had to take them somewhere). He said he wanted the proof with both my names NOT one name or initials. The question was how , when and who changed my address, what was the reason behind, why I was not notified ,was there a proof on the time of change? He said he had no idea .... I then recalled that it has been months to hear from my bank and wondering if my accounts are still in place. More than that I take this as a breach of confidentiality as the people who reside in the address used, now know my pocket as my mail is sent to them.