@Lyka ********
>but why they stopped insisting I pay them 2k when I told them officer at counter 46 said so
In the Thai culture, saving face is important, and it wasn't worth the risk of the immigration officer to lose face if the officer at counter 46 said you don't need to pay a fine.
The ONLY way you'd know if you have to pay a fine or not is to ask Counter A. Those are the people you need to ask.