@Thijs If your subscription is valid or you have not cancelled you subscription then you should be able to download the theme zip file form your themehorse account page in ‘Available Downloads’ section. If you are still having some issues, then please contact us via our https://www.themehorse.com/contact-us/.
Unfortunately there is no available downloads section in my themehorse ccount page.
I have also already send a message at the page you suggested but have not received any news.