I have entered my purchase code and username (case sensitive) in order to have support (still 5 months remaining) for a theme I purchased June, 2020.
Please let me know what I can do. thanks
Please contact your purchased theme Author and let them know that you are facing issues with purchase code to get support. you can let Author know by posting comments going through the theme Comments page. theme author will assist you.
Also you can check How to Contact Author.