We announced back in December of last year that the store would be going away and individual algorithm sales would stop. We made this official back in April. All we did now was actually remove that portion of the app that did not have functionality. The only way to add to your H9 Core is upgrading to a Max via the Max-out program.
Login to your Eventide account to find out what your price would be: https://www.eventideaudio.com/store/upgrade-h9