The assets that you claimed are no longer free, which is why they’re not showing up when you filter for free assets. That doesn’t mean, however, that you don’t have access to them.
For example, this asset:
It has a price when looking at search view (this is a known issue that affects users who’ve claimed all Megascans), but when I open the listing, it shows as being something that I have a claim to.
Try opening a listing for a for-purchase Quixel asset and see if the listing page indicates that it’s “Saved in My Library”. If it does, things are as they should be. If it doesn’t, please contact support.