Without Match, how do I remove songs from the cloud?
You can have her delete it / stop it being stored in the cloud (see this help page: https://support.apple.com/en-gb/HT201323 ) - basically just click 'Also delete this song from iCloud'.

Alternatively keep them in iCloud but just turn off Automatic Downloads as suggested above by GeF.

EDIT: Remember, choosing to 'Also delete this song from iCloud' doesn't mean the purchase is wasted - you can always re-download previously purchased tracks.