TravelPledge emails each winning bidder their certificate upon checkout in TravelPledge. It's possible a winning bidder does not receive the certificate if you entered the wrong email address or the email was caught in a spam filter.
You can send a certificate a winning bidder again with the following steps:
Navigate to your Events tab.
Click View Details next to the event where the certificate was sold.
Click Print Certificates.
To print the certificate to a PDF, click Print Certificate. To resend a certificate instead, click Resend (you'll be prompted to edit the email address).
Note: You will not be able to print a certificate if you still owe money for the sold item.