[doublepost=1488435113][/doublepost]Figured it out, finally. Following works for iTunes 12.5.5.5, it may work for other versions.
1) Go to iTunes, select "Store" page.
2) Top right of page, select "Account", log in to your account if you have to.
3) On "Account Information" page, look down toward bottom of page, there's a section named "Settings"
4) In the "Settings" section there is an item named "Subscriptions", click the "Manage" link on the right of it.
5) Find "iTunes Match" item on "Subscriptions" page. Cancel the subscription.
iTunes->Store->Account->Settings:Subscriptions:Manage->Subscriptions:Active ...