You can't: flag is not one of the filters for game seeks
How do I configure my account to not play against players from a certain country?

If you contact Support, they'll generally be happy to refund the unused portion of your premium subscription.

Suppose I don't want to play with players from a certain country. How I should configure that?
you can simply abort when you get paired with them in the Open Pool. I don't see any other solution for you

Honestly , i have no answer to your question but to be complelety honest there are certain countries players that I don't trust to play fair (I won't name them). Maybe the solution is play at 4 am in the morning (or whatever hour suits you to avoid them)

yeah exactly
this is just racism but different
just because the site doesnt allow racism you cancel premium?

its not racism, its just what he wants. But it is racism to think certain countries cheat more then others, without any proof, as Ron is implying

yeah exactly
this is just racism but different
just because the site doesnt allow racism you cancel premium?
I think the OP was referring to location, not race. Apparently it needs to be pointed out again that race and nationality are two different things. Ron had a good suggestion, play at times when it's less likely to be encountering people from that specific location.
It's no different than choosing a restaurant for dinner. It's very possible someone may wish to not associate with establishments of a certain location, for whatever reason. That's certainly their right.

yeah exactly
this is just racism but different
just because the site doesnt allow racism you cancel premium?
I think the OP was referring to location, not race. Apparently it needs to be pointed out again that race and nationality are two different things. Ron had a good suggestion, play at times when it's less likely to be encountering people from that specific location.
It's no different than choosing a restaurant for dinner. It's very possible someone may wish to not associate with establishments of a certain location, for whatever reason. That's certainly their right.
i see

Honestly , i have no answer to your question but to be complelety honest there are certain countries players that I don't trust to play fair (I won't name them). Maybe the solution is play at 4 am in the morning (or whatever hour suits you to avoid them)
You are just a 700 rated noob who knows nothing , People who cheat won't be at a pathetic rating like yours so you can play freely without any doubts

Suppose I don't want to play with players from a certain country. How I should configure that?