They are doing what they're supposed to. And what you are supposed to do: go home. What do you think gives you the privilege to stay long term in Thailand on exemptions and extensions?
All immigrations offices should refuse the extension in this circumstance.
yeah strange. I do vaguely recall that some border was indeed not aware, but it's a bit much to advise against using them to activate a DTV indefinitely. Everyone should by now be aware that it exists.
Besides, you cannot not use a visa if you have one. If you have a DTV, they can't even stamp you in otherwise.
And I hope we do not have a discussion about whether you can exchange an entry stamp for a different visa at a local immigrations office? This really is established knowledge.