Every time you enter the country you receive a new 180 day stamp, that does not cost anything. However, if you are in the country for 180days and want to extend/stay longer (not leave the country) you go to the immigration office and pay 1,900 baht for the extension
Nah, you said “So maybe just UK embassy is like this. I called once and they responded immediately”. You never made mention of Slovakia. Since you reference UK in the first sentence, it is implied it is referenced in the second,