Sketchup for Schools: erased models?

Hello! I teach a design class with Middle School students in which they create 3D designs of homes. I have had 2 students find that, partway through creating their final projects, their models dissappeared from their Google Drive folders with no possible explanation why. These are two very exceptional students and I watched them work on their designs (successfully opening and saving them each time) for many days before they suddenly dissappeared. They may have tried to open these models at home on a different computer (we use Chromebooks at school) - that is the only possible explanation I could think of for the issue, though I do not know why it would be a problem.

I tried during the school year to contact Sketchup for Schools’ design team and did not get a response. Their User Agreement states that models are stored on Google Drive and therefore Trimble, the organization that designs the Sketchup for Schools service, is not responsible for storage of these models. I would love some guidance on who to contect next, as this is an issue that will prevent me from teaching the course next year altogether if I can’t solve it before the fall. We only have Chromebooks available so using a different version of Sketchup is also not an option.

Alternatively, if there is a different web-based platform folks recommend, that would be great. Sketchup has been great because it has the visual orientation that looks like you are looking at a landscape, and you can georeference models to locations to then study the shadows at those locations throughout the year. This is a really important part of our course that I would have to likely redesign completely if forced to use a different 3D modeling tool.