There is a private international visa processing company called VFS that process the DTV + other vidas for the Thai embassy in Kathmandu. They are located in the 3rd floor of a new shopping mall in Thamel area.
VFS handles the applications for the DTV in Nepal and they are a shower of ( Redacted ) and known to be overly pedantic. Someone has to pay for that shopping mall they occupy in Tamal.
Once I saw they had their grubby little hands in the application process, I looked elsewhere.
Just interested to know if you actually contacted the Embassy of VFS.