Google has added a new feature on their Google Music platform.
Any music that you remove from your account is now stored in a trash section for 28 days.
You can recover any deleted music files from this section during this time period. After that Google deletes it permanently.
One weird thing though… The same policy applies to your purchased songs. Google warns that any permanently deleted purchased song would be removed from your account so if you want it, you would have to purchase it again.