KabyLake: I already wrote that I used my main account not only for playing games. I had a professional software for video rendering like Sony Vegas Pro and so on...
If you do in fact have a valid license for that, contact Magix support and explain (in one email, and no follow-ons, unless they specifically ask you questions) what happened to your Steam account. They can - and perhaps will, especially now that the software isn't owned by SONY - decouple your license from Steam by cancelling the existing license and granting you a replacement one. That is actually not an unheard of thing with licensed software - canceling a license because a legitimate user has lost access to hardware or 3rd party software, and then issuing a replacement. There's no guarantee of course, but it's worth a shot if you're a legitimate license holder.
At the very least, it'll be more productive than continuing to complain about it here. We certainly have no pull with Valve.