Most Thai people are very polite and understanding. Smile and be nice they will understand your concern and apologize. The ones who aren’t polite …good luck
Suki teenoi is sworn by as far as locals go. Don’t expect crazy good service especially not speaking Thai it’s decent to good depending how picky you are.
Use a visa service. If you try to do this all yourself you’ll experience roadblocks until you “play ball” and pay. The visa offices have relatives and associates in the main hub until you pay to play they will slow you down. Conversely, once you pay life is easy.