When someone says you hurt them, your first job is to listen, not to build your defense.

Hearing that you caused harm sets off an immediate scramble for context: what you meant, what sort of day it was, what they did first. All of it may be true and none of it is what is being asked for. While you assemble that case you are not listening, and they can tell, so they either say it louder or stop saying it.

Hold the defence and ask one question about their side instead. Say what you now understand before you say anything about your intentions. If the context still matters later, it will still be there later.