On my computer, the account info page of the iTunes store shows that I have a current iTunes Match subscription (set to renew in February of 2013.) However, when I try to enable iTunes match on my iPhone 5, it say's I am not subscribed to the service. All devices are using the most current softward version and I am using the same Apple ID. How do I resolve this issue?
Not sure if you tried this but I was having the same problem with iTunes Match on my iPhone 5. I fixed it by first connecting it to my MAC. When I connected my iPhone i saw that the "iTunes Match" icon popped up again in the navigation bar on the left (under the "Store" category). I thought this was funny because this is only an option if you haven't activated iTunes Match on the computer or if you haven't registered for the service. Since I already did that I found it was odd that the icon would show up again. Sure enough I clicked on the iTunes Match icon and the main display screen in iTunes went through what seemed to be a quick auto logon process and the iTunes Match icon disappeared. After that I had a hunch and went back to my iPhone (still connected) and tried to activate iTunes Match and this time it did it. Still seems to be some kind of a bug with iOS6 but it has fixed the problem for me... for now...
iTunes Match not working on iPhone 5/iOS 6
