Just out of curiosity, Felicity, which pronunciation did your teacher tell you - 'Zee' or 'Zed'? And, more importantly, who told you that this pronunciation was wrong? Whether your teacher told you it was 'Zed' or 'Zee', he or she was right. It was the person who disagreed with your teacher who was 'wrong'.

In Australia we use both. I find "zed" is more common, except when reciting the alphabet in order ex. "ex why zee".

There is the British English way of saying it and the American way . British English Z sounds like (zEd) like the name ED American English Z sounds like (zee ) like meet

In American English it is pronounced zee. In British English it's pronounced zed