So I need some advice

I work at a grocery store , bagging groceries and today this old man was trying to explain something so simple to me like if I was a baby a child or someone who didn't know English at all ... I'm Puerto Rican btw , so because of how he was explaining things I was having trouble figuring out what he wanted . Turns out he wanted his ice cream in the plastic first and then inside the paper bag . So when I grabbed the Ice cream to put in the plastic bag he grabbed it out of my hand so was angry snapped the paper bag open in my face he was acting so violent and then said you know I don't want my Ice cream to melt like last time. ._. I didn't say anything , but like how would you deal with a customer like this . I just feel offended I don't know why he acted that way towards me wether it was because his ice cream melted some other time or because my race or I just don't know .