It happened to me also, actually after the 2 doses everything was fine and then after my booster shot, it registered as i was thai , my gf called back the hospital and everything was fixed within a few hours.
The thing is you need certain time frames in between doses so that means that you would be stuck here for a certain while and eventually your tourist visa will run out also. Isn't it Johnson's that requires only one dose or have you thought maybe going to Cambodia to find that required vaccin and then go home.
you have a credit card or a debit card???.....i don't think many foreigners get credit cards from thai banks. A debit card with a Mastercard or Visa logo is not a credit card.