Hi Ben,
Wish we could talk dutch, as its a bit easier. But english is the main language here, so we have to stick to this for now, unfortunately.
First, I like to tell you we are not from Presonus. We are users just like you. So when you do not get a quick response, don't blame PreSonus, for this is an user to user support page. We don't get paid for this.
Second, I understand you have issues with the shop. I have the same issues on a totally different system with a total different version. So, it's safe to assume this is a server error, or the update didn't implemented this section well.
However, I did manage to get it working a few times by trial and error, so I could retrieve the soundvariations for BBC Discovery. It costed me a little bit time by closing and starting S1 again. I suggest you should try that out for the time being, but also suggest you contact PreSonus directly to issue this problem.
In all my experience, PreSonus listens to their customers.
Second, Presonus is constantly improving and adding unique things. So, yes it's possible they sometimes release bugs, even with 'simple' things like a shop. I ask you to give it a fair chance for them to fix it and make sure you have a plan B ready for your project.
I don't like to attack other DAWs, but I can tell that no DAW is bugfree forever. There are always minor hiccups, but I do assume it's going to be fixed in a quick tempo, especially when PreSonus is going to be notified on the issue. I expect that from every professional audio software developer, by the way.
So I am sorry I could not help you, but I do hope I've pointed you in a direction, and made the situation a bit more acceptable.
I wish you good luck on your project, Ben!
En een hele fijne avond! ;)