I accidentally purchased two licenses

Hi,

Thank you for posting your query here.

Please contact Adobe Support Team and they can assist you regarding Cancelling the Duplicate Subscription. You may contact Support Team by clicking on : https://helpx.adobe.com/contact/support.html for chat or https://helpx.adobe.com/contact/phone.html
-click the chat icon at the bottom right of the page to open a chat session
-the chat icon looks like '3 dots inside a circle' at the lower right
-type AGENT into the chat window to connect directly to a person rather than the AI

Hope this helps. 

Thank you.