TIFU unknowingly calling a customer a slur

To be clear, this happened about last year but i still think about it because Spanish is the language of all time.

For context, i'm a Venezuelan-American. I was born in the US but i was actually raised in Venezuela for about the first 10 years of my life, this mainly consisted of visiting the family over the summer vacation (although i did spend one full year there when i was three, in fact my earliest memory ever is of my uncle tricking me into drinking beer at age 3 in a town called El Tigre). Obviously because of this upbringing i grew up fluent in both English and Spanish. The thing about Spanish though is that when you learn it, you're learning it, you're learning a specific version of it. English has it's regional differences too but at least in my experience it's not as big. Though the Spanish i speak is Venezuelan, growing up i at least knew that Colombians call beans "frijoles" instead of "caraotas" and that Spaniards use the "vos" prefix. Once i became an adult though, i came into much more contact with various different versions of Spanish.

From confusing my coworkers by asking for a "pitillo" (straw in Venezuela, cigarette in Puerto Rico), getting confused when an Ecuadorean (i think) came into the store looking for a "buso" (jacket). But all of these usually result in a good laugh and we move on. Except for one time where i think the guy i accidentally offended was gonna take a swing at me. In the store i work at, we do offer free tailoring with purchase. This Salvadorian man came in looking for a suit and so we go to take his measurements. Now, we're speaking Spanish here" so i asked him "por favor quitate las cholas" or "please take of your sandals". And there's the fuck up: he looked at me like i just called him the N-word. Because he could be heard across the store about how what i sad was bad, the manager had to come in to defuse the situation, explaining to the guy that i'm Venezuelan and we say different things or our words have different meanings. Thankfully it was resolved and he was able to get his suit.

When i got home, i went online and searched if there were other meanings of the word. See, in Venezuela, as you have read, chola is slang for sandals. Yeah we say "sandalia" too but more often than not we're saying chola (unless they're from Maracaibo, that's the Quebec of Venezuela). As it turns out though, in several Central American countries, of which include El Salvador, chola/o is an indigenous slur. Well. That's the day i learned something. That said aside from being more careful, i'm not really sure what i'm supposed to do about it because that's not what it means where i'm from. It's like an Englishman not knowing the f-slur in the US does not mean what it means in England.

tl;dr, nearly pissed off a customer because a word that has an innocent meaning in Venezuela is a no-no word in El Salvador.