I got mine approved going through Fight EVO360 Pattaya, I received a paid invoice, signed invitation letter, and they sent me a copy of their business documents showing their registered with the sports authority and business license. I went to Laos and was approved in 3 days with no problem
I got mine from Fight EVO360 Pattaya, there was no extra fees for the paperwork and they give a guarantee if denied with proof you can get your money back