There’s no charge. You should call your credit card company to discuss the charges and reverse any that are unauthorized 

You shouldn’t be charged for the app.  The only thing Sonos charges a monthly fee for is Sonos Radio.  If you inadvertently signed up for that service, here’s how to manage that account (including how to cancel)

https://support.sonos.com/en-us/article/manage-your-sonos-radio-hd-subscription

I am checking that out.  And I do listen to Sonos Radio, although I can’t figure out how to stop the station I chose, so I don’t especially like it.  I do have an unexplained Apple charge, so I think that this is the problem.  I erred in the amount being charged, however. It is lower than $19.99.

Thank you