erigaud
Honored Contributor

You can try doing the following . 

Step 1: Navigate to the Databricks Help Center (https://help.databricks.com/s/contact-us?ReqType=training)
Step 2: Provide the requested information
Step 3: For the Training Issue, select “Certifications”
Step 4 :Explain the course you completed to get the voucher
 
Let me know if it works !