How do I support it if I do not have another country added to the database? Your theme sends the information to the osclass core that processes it in the database and it processes what gets from the theme, right?

@Romeo
If country is not in your locations, it does not mean listing cannot be published there. You can check database structure of listings and their location to understand.

Well, that's what I'm saying, how do we do that does not happen with the ads, who gets that script. I did not ask you to solve the problem but how do you know how osclass works what the indications would be good from you

@Romeo
Theme is limiting locations using javascript (if you do not select -> error). However, it is possible to disable javascript in browser (addons like adblock or different, do not know) that disable validation as well. In such cases it's needed to place extra layer into submission function to check wheter  location exists in database, if not return it back.

In vain, at this stage I lost myself, irretrievably, and let me down, thank you for trying to help me.