3D Warehouse: “You can’t download this file due to an upload error” (owner) + no access to Support cases

Hello everyone,

I am the owner of multiple (private) models on 3D Warehouse. For some of these models, the Download button is greyed out, and I get the message:

“You can’t download this file due to an upload error.”

The 3D preview also doesn’t load (only the 2D thumbnail is visible).

I am using Firefox. I also cannot open a SketchUp Support case (both the Support Center and the contact form are blocked for my account), because I’m using a very old SketchUp Pro 2014 license that was originally purchased by my former employer. I’m now retired and no longer in contact with the employer/reseller.

Models affected:

Screenshot:

Question:
Is there any way to restore these uploads so I can download the models again? Or is there any workaround to retrieve the original SKP file?

Thank you in advance,

Bep