iExplorer kept crashing when I tried to delete the iTunes Media files, so alternatively this solution worked for me:
1. Make sure iTunes Match is turned OFF on your iPhone. (Within your iPhone, go to Settings>Music>iTunes Match - OFF.)
2. Plug in your iPhone to your computer via USB.
3. Open iTunes, in the left hand column under "Devices" click on your iPhone's Name.
4. Scroll down to Options. Click on "Manually manage music and videos"
5. Go to the music tab and click "Only selected playslists, artists, albums, and genres."
6. Then below, choose one Artist to sync, otherwise this process will take some time.
7. Click Sync (If message pops up saying "This device is already synced to another iTunes Library..." just go ahead and continue with the Sync anyways.
8. When Syncing has finished, you can go onto your iPhone and navigate to Settings>Music>iTunes Match - ON. Enable iTunes Match
9. Open the Music app within your iPhone. iTunes Match should load and start working!
Download is an "option" now, before as soon as you played a song it started to download, this was a huge peoblem for those with idevices of small GB count, for me it was just annoying.
But now instead of downloading individual tracks you musct download full albums, this will suck in double albums with up to 30-something tracks.