In Thailand, the ATMs dispense the cash, then the receipt, then return your card. Many people have walked away with the cash and not waited for their card to be returned. When that happens, the ATM sucks it back in and you have to call the number on the ATM to get your card back.
Go in the morning with your passport, a passport photo and 1900 baht cash, complete the form and drop off your passport, the photo and the cash. Come back when they tell you to come back. I suggest you wear pants to be safe.