Several GB of files just disappeared in icloud

I have been using icloud for a while now. I had several years of files, photos, projects etc. that I ignorantly saved on the cloud. Years and years worth of information and data. I also have a windows PC that I have synced with the icloud using the app.

There was a system upgrade of the icloud app in mid-January which required for me to re-sign in etc. All my files were there at that time.

A week ago when I tried to access the files, they all seem to have disappeared. The funny thing is not all files have disappeared, but almost 90% of the files have. The folders however appear to be in place but the files, photos, videos, documents etc. all gone.

As soon as I noticed it, I went on to the computer as well as the cloud to locate these files. I tried to go and retrieve my files from the deleted folders etc. but it is not there. I called in apple helpdesk (who kept me on hold for hours and hours), then sent it to engineers and they cannot find it.

How can apple lose these files? Is there any way of getting these back????

I must mention that there has been absolutely no drop in my file storage with apple.. it infact has increased..

Now apple has washed their hands off this issue saying they cannot recover the files they lost!!