I should preface this with the info that my wife and I share an iTunes account & our assortment of ios devices are all linked to it.
My wife's iPhone keeps on telling her that the subscription expired - we are well aware of this and more than happy with our choice, but it seems her iPhone is not. Even though there is only a couple of hundred tracks physically stored on the device the Music app shows our entire music library, just as it used to when I was subscribed to iTunes Match. At the end of every song she gets the pop-up... "Your subscription to iTunes Match expired on...." Not very useful when she is using Google Maps to navigate from A to B as she has to do everyday.
I have turned iTunes Match off in settings, under both iTunes & App Stores as well as Music. I have restarted the iPhone, deleted all the music data from it and reloaded it. I have even tried to turn iTunes Match back on in the vain hope that the iPhone might realise that I'm not subscribed and stop pretending like I am.
My iPhone just shows the songs that are actually on the device. This is what we want for my wife's iPhone.
The only thing I have not tried is to restore the iPhone. I am trying to avoid this if at all possible as.... well tbh the iPhone restore is AWFUL as you then have to spend HOURS trying to find your apps as it seems beyond Apple to restore the apps in the layout that you backed up.