I am having similar problems. Doing a search of on the Apple web site got me the suggestion to turn off iTunes Match and then turn it on: Mac: Hold down the option key, then choose Store > Turn Off iTunes Match from the menu bar at the top of your computer screen. Turn iTunes Match on by choosing Store > Turn On iTunes Match.
When I try to follow these instructions there is no 'Store' in the menu bar. If I go to iTunes Store from the iTunes Menu the only option is to purchase iTunes Match, with no indication whether you already have. When you go to Accounts you can find that you have iCloud Music, and which devices are subscribed, but with no text saying that iCloud Music is or is not the new name for iTunes Match.
My original problem that made me start looking at this was trying to play a Playlist on my Apple TV. I found the playlist but it only had 5 or 6 songs in it, instead of the 20+ that are shown in iTunes. Some of those missing songs were purchased through iTunes, and appear (right now) on my iPhone, so I would expect those songs at least in that playlist on my Apple TV. I was going to to do an iTunes Match sync from my desktop computer (an iMac) and see if that cleared things up, as I had done in the past. I could find no way to upload or sync my iTunes Match library, and I couldn't find any help initially listed under the Help menu on iTunes. I don't know where to go to find information right now because at least some of the help sites on Apples own Support pages appears to be inaccurate, if you have updated iTunes recently, and the phrase 'iTunes Match' seems to be disappearing from the various Help menus on iTunes, iPhones and Apple TV.
