You can disable transcription projects from your profile: 

1. Sign in to your BLEND account. 
2. Go to Control panel -> Edit profile -> Language skills -> Transcription skills. 
3. Remove the languages listed and click Save. 
4. The Transcription Skills section should be empty as shown below:

      5. Email us at support@team.getblend.com to verify that your transcription skills were removed.

    Only after our email confirmation, you won't receive new transcription projects.