Maybe you should have read their advice on the website before you send your application by post:
From their website:
"KSP Self-Service is a service to facilitate the public. Those who wish to practice the education profession Education professionals
with 24-hour service. You can request various services through the Self Service system by yourself
. There is no need to send documents by mail or travel to the Secretariat of the Central and Provincial Teachers' Councils."
As you might know that even if they received your documents once, it might be they lost it somewhere and won't want to lose face by admitting that.
Keep on flogging a dead horse and hope something will change.