I was using a commercial, pay-per-month backup solution for several years. Recently I had to restore some files. The software failed and did not restore important files, showing a cryptic error message for which I cannot find any help anywhere in the internet. I tried to contact support several times, but there's no answer so far. So it turned out I lost the files, and I didn't have any reliable backup for all those years.
I would like to warn other users which might be using this product. Of course I'm feeling angry and this is part of why I want to do this, but another thing is - there might be many many users there which are using this software and have no idea that they have no backup at all.
My question is, how can I inform other users about this? Does this belong to Server Fault site, or Super User site, or nowhere at Stack Exchange?