Looks like they have finally taken down the page for the sign-up.
Apsona stopped supporting/developing Shop Admin a long time ago to concentrate on Salesforce, but left the Shopadmin code on their server. The code still works/is still on their server but evidently they are not interested in new users.

If you have your old Apsona id, you can set it up using my files on Github, but really you should invest your time in DBIO for imports/exports:
https://www.zen-cart.com/showthread....Support-Thread