How to keep iCloud Match but stop phone syncing all music files?

When I first set up iCloud Match, I could access every song in my library (over 20,00 selections) because they did not have to be on my phone. However, now when I sync, the phone downlaods music files until it is over limit for memory. So the only songs available to me are the songs it had room to download. And, since the file is on the phone, there's no point to Match. I have iCloud Match activated in the sync settings which gives me no other options for music. I cannot delete the music from my phone. Did Match change? It seems the whole point of Match is to sync the library listing but allow you to access them via the cloud. Which is how it works on my iPad and, as I mentioned, how it worked originally on my iPhone. I have an iPhone 4 and a 2007 MacBook, all with the latest software and updates.Is there some way to rectify this? Thank you.