https://www.namecheap.com/support/knowledgebase/article.aspx/9490/71/how-to-cancel-an-ssl-certificate-will-there-be-a-refund

Generally, to have a certificate cancelled and refunded, you just need to submit a ticket with us to our ‘SSL Certificates – Sales’ department.

Please do not forget to include the order or certificate ID in the ticket for verification purposes.

To find the ID activated or inprogress certificate, please perform the following steps:
1. Sign in to your Namecheap account and navigate to Dashboard  
2. Locate the domain name which is used as a common name for your certificate 
3. Look for a certificate icon and mouse it over > from the drop-down menu click on Manage
4. In a new window you may find your Order ID and Certificate ID (6- or 7-digit code in the first column at the bottom of the page)

If you would like us to issue the refund to the source of payment, you should also mention it in ticket.

A refund for the certificate can be requested within 15 days after certificate issuance. If a cancellation request is submitted when a 15-day grace period is over, the refund will not be issued.

The certificates which are activated but not issued yet (the status in your account is "Purchased") and non-activated certificates (the status is "NewPurchase") can be cancelled and refunded *only if you request cancellation within 90 days from the purchase*.
The cancellation request which is requested after 90 days period from the purchase date will not be fulfilled.

Cancellation process is not instant, we can cancel and refund certificates right away only in case they are in *New* status.

In order to find the ID of the non-activated certificate you would need to open the Certificate List: