True, once you have set up a Common Hop Link, the Seller Admin won't let you disable it. Our Development team can probably do that for you, but bear in mind that will mean that any affiliates who already obtained a Common Hop Link for your program will find those links no longer work, and in the future if you disable any product-specific Hop Links or delete those products, any Hop Links issued for those products would no longer be able to continue working in fallback mode by redirecting buyers to the Common Hop Link URL. You might consider just setting up a simple page with links to each of your product pages, then make that your default Common Hop Link URL.
If you do still want us to disable your Common Hop Links, email your request with your E-junkie account password, or your original activation code would suffice if you still have your original "Account information" email from us:
https://www.e-junkie.com/ej/contact.php