Hello pewepro and welcome to the forum.
Maybe there is some confusion here. In your first post you said you were looking for ST2 L or XL. I am 99% certain that the only difference between SE, L and XL is the contents of the sounds library. The actual ST2 software is the same. Support was therefore correct to respond to your request by saying that those ST2 products are not for sale any more.
As for the legacy installers, you should find the ST2 software installer in your User Area / My Products section. I do not know whether those installers will run on your system. You may need to use one of the older installers (click "Past releases"), as Peter mentioned.
Legacy products (that is those that do not use the Authorization Manager) can be registered / authorized here:
https://www.ikmultimedia.com/registration/If you wish to get the ST2 L or XL product, with the bigger library, you could try the Sell / Buy forum at KvR Audio.