iCloud drive - cannot delete files

Hello there, I am stuck with a problem: I would like to downgrade from my 200 GB storage plan with Apple to just 50 gig or maybe even the free 5 GB. Now I transferred all my files from the iCloud drive to a local hard disk and then de-activated all iCloud services in the control panel on my Mac. I also cancelled all iCloud services on my iPad and iPhone. With the aim of course, to reactivate them as soon as my subscription would have been changed.

So, now the problem: When I open iClod drive on my Mac or via the Internet, the drive appears empty. When I open the iCloud control panel and view the details, there appear 169 GB used space with documents and photos etc. There are even data from apps I deleted years ago. When trying to delete them within the control panel it says "...could not be deleted. Try again later". Very funny indeed, this message is so typical...

So since I am no bit wiser I hope someone came across this and might be able to help. Thanks in advance