What I have uploaded to my site is missing the doksoft_uploader/config.js file and I can't find the original download link. Should I get a refund and purchase it again or what?

Hello, `config.js` in not a part of DOKSoft plugin, it is the part of CKEditor. You can find this file in CKEditor's root folder.
Maybe you are looking for `config.php` when try to configure DOKSoft Uploader plugin?