You wait until they move or run out of time and don't play them again.
Bad etiquette
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your opponent has the same ego than you, you were lucky and he is angry , good etiquette does not exist in the human mind. His attitude probably is not socially acceptable but he is acting naturally and you hide youself in a behavior of a gentleman.
The essence of capitalism is competition , chess is competition, there are etiquette rules but if you can violate it you will . If i was your opponent probably i would tell you , " learn to win and xxxx xxxx xxxx mouth xxxx".
Anyway , i recommend you to stop to play chess and here is the reason .
What do you do if your opponent will not resign despite being one nice away from mate and simply keeps offering draws over and over again ?