I've long had a policy of not dealing with folks who lack the ability to communicate in standard English. It's a good predictor of problems to come.
Well, everyone make their own decisions, but for me that is not a hindrance.
On occasion the situation has been reversed - I have done transactions over the net in other languages.
And as I know I am thus at a disadvantage, when using one not my own I am careful to
a) read everything
b) not hide my intentions
c) be polite
...and if the other party does likewise a deal is usually struck (failure at c however is fatal).
This was the way computer enthusiasts began, back in the days of Fidonet and 300 Baud; it seemed everyone was nice.
Then of course videogames with their "shoot-to-kill" and "everyone-else-is-a-monster" themes (can you spell "DOOM"?) produced multiple generations of screen names with no manners or morals.