YOU ARE NOT PETER ! GET OUT OF MY HOUSE
It is very hard to hear the difference between Ő nem Péter and Ön nem Péter
Just one facet of any language spoken at normal speed you have to get used to, I suppose. At least Hungarian is one of the more discrete languages unlike, say, French, with its liaisons and numerous homophones.
Did not accept "You are not Péter". Both should be accepted.
Isnt this supposed to be: He is not Peter?
ő = he/she/it
ön = you (singular, formal, the verb is conjugated as third person singular)
When should I use "Ön" and when "te"?
When talking to your boss (for example) you use 'Ön' but for a friend use 'te'
It accepted én for me a moment ago even though that is clearly wrong.