iTunes Match is a trainwreck - and has been for over a year
I first contacted Apple last year - iTunes Match was caching Music streamed by my phone (but not downloaded), but refusing to clean itself. My storage would decrease progressively meaning I'd have to restore my phone about once every month or two. iTunes would recognize my phone as having up to 2.6GB free space. The phone would say I had as little as 80MB.
Multiple tickets opened on that. The engineers got my logs back in October 2014 - never got a response on that. A few Senior iOS reps have been perfectly nice, but then went M.I.A.
When I upgraded to iTunes 12.2 - even though I waited for the patch - it still royally screwed my library. I have thousands of songs assigned ghost ratings based on album ratings I'd never input. Many of the album ratings are for Unknown albums assigned to random singles or even sound effects just happening to be in my library.
I fixed that by downgrading iTunes and restoring an old library itl file I pulled off TimeMachine. But then iTunes Match went down for all of yesterday - meaning I lost all my music to the cloud while their system status was supposedly up.
Around 6pm yesterday iTunes Match came back. But when it redownloaded to two of my computers, it sent along even more corrupt libraries, which are now different between my computers, phone, and iPad.
Through all of this I've spoken to more than a handful of Senior iOS, iTunes, etc. reps, handed over my logs to engineers multiple times, screenshared, etc.
C'mon Apple I basically just throw my money at you. Both this software - which I pay for - and this support is unbecoming of your brand. Halp.