What do you understand by a stamp ? Before the e-Visa system was introduced, there were stickers. Nice colorful beautiful stickers the size of a passport page. Do you have a sticker like this in your passport?

Why not simply apply for a new passport instead of consciously putting yourself in a complicated situation ?

At which consulate did you have the interview?

Did you take a photo of the entry stamp with your phone or did you scan it with a scanner?

Hotel reservation for Vietnam or for Thailand?

@Boaz ****

Thank you for your quick answer. Can you tell me please what they wanted to know from you at the interview ? What questions did they ask you ?

@Dany *******

2000 THB fine is a lot for me. I always report my 90 days on time.

Have you been to Vientiane?

@Paul ******

I am very sure that you will not get away with just ignoring the 90 days, there will be some kind of consequence, I don't know what it will be, but there will be a consequence

I would go to the local immigration and pay the 2000 THB there. They won't red flag or do anything to you because you went to immigration voluntarily. But if you wait until you leave and you come across an officer who is having a bad day and doesn't like foreigners anyway, he will take the 2,000 baht fine and even red flag you. That doesn't mean they will not let you in again but they could ask you more questions than normal. Who would you pull out into an interrogation room ? A person who always followed the rules or people who had 90 days overdues ?