Tell how well is my RP pronunciation

Well, I can certainly see that you are not a native speaker. You have that Chilean accent. For instance, when you say CHILE, it's more Spanish than it's English. Also, the way you say NATIVE SPEAKERS is more French then Spanish, and it certainly isn't English. And you have grammatical errors. It's TEACHERS DON'T understand you, not TEACHERS DOESN'T understand you.
I don't want to discourage you, but you have to practice. Bear in mind that it is VERY HARD to ''get'' genuine British/American or some other accent after 20, 21...