Programming Questions? Ask a Programmer for Answers ASAP
How's it going.Let me read of your question. Give me a minute.
Can you give me the URL of the site please?
If you have access to the system that hosts your website, the theme can be reactivated through the database.
Please see http://sakinshrestha.com/wordpress/choosing-default-wordpress-theme-through-database/
Please shout if you need more help.