Did you have a DocuSign Account associated to that email address used 3 1/2 years ago? Basically, if you had a DocuSign Account that used the email address where you proceeded to sign a document, the envelope would still be present in that DocuSign Account unless the envelope was deleted or the account closed. Envelopes can be found under Manage, then use the Search functionality to locate based on time or envelope id or perhaps document name or email subject.(https://support.docusign.com/en/guides/locate-documents)

Also whenever Sending or as a Recipient you may have received the final document in a completed envelope notification.

In conclusion if you did not have a DocuSign account and you do not have the email notification from 3 plus years ago, you could ask the company or person who sent the envelope to look and forward you a copy of the envelope/document.