the issue sir, is that on your first comment you made it sound as if you could just jump in a plane to Thailand and showed up at the airport to get your 30 days tourist visa. Somehow you omitted the many steps required to even get in the plane. That’s all
Sorry my agent is in Chiang Mai ... but I am sure there is such a service in BKK. I tried 3 times to do it myself but failed...not 'cuz I did not have all the papers, but the PPL at immigration keep changing their own rules. I got an agent I paid 4000thb and it was done without problems. Good Luck.