Syncing unavailable spotify songs with local files

[hyperliteBo]

Short rant first: F*CK SPOTIFY AND ALL THEIR LACK OF USER FRIENDLINESS, BECAUSE THEY ALMOST HAVE A MONOPOLY ON AUDIO STREAMING THEY DON'T GIVE A SH!T ABOUT THEIR CUSTOMERS IT SEEMS.

My sincere apologies for that, I had to get it out of my system...
Now my problem... there is an album on spotify where only one song is available (I guess due to some rights or something) and when I try to play it, it says that it's unavailable but that I can import it if I have the local file... how do I sync that?

I have imported local files successfully (had to buy the album next to paying premium Spotify -_-) they show up and play fine both in my Windows app as on Android (downloaded the local files).
It even recognizes all the metadata AND album cover but fails to connect the dots and sync it all together...

I have some other local files from another band that's not on Spotify at all and while they play fine on all devices I also can't seem to find a way to integrate them with my library, it would be nice to have that artist show up in my artists section or my search results but it doesn't, I can only find it if I make it part of a playlist.
This while Spotify is able to see all the right meta data and album covers of that band as well...

Any help to resolve this utter frustration is most welcome.

[AeroZ]

The feature that linked your local files with Spotify catalogue versions was removed about a year ago. 

[hyperliteBo]

For fox sake, they really are slowly killing all useful/user friendly features aren't they... -_-