how to cancel icloud plan?

i was terribly lacking in details, sorry.

at first i was trying to down grade to force Apple to delete apparently 31gigs of data that just says "Documents", yet its always empty when i go into it on my laptop and online on the iCloud drive. I actually busted it on the web making it crash, because I kept forcing it to delete and it would pop back up until the a small window shoulder it crashed. So as it stands unless i figure out how to remove this ball of data in which I've never had 31gigs of data in, but i have had multiple other MacBooks over the years (all with the same login ID account), so it should show me wha the 31gigs is. Either way, it did not give me a option to downgrade to free at first, but on my phone it has the option, but won't let me select it as I'm over the original 5gigs for free. on my laptop the option is NOT there only on my phone. the lack of the option to downgrade on my laptop was the reason for this email originally, thinking they was trying to hide it, but its because I'm over the 5gigs.

any suggestions on my current issue?

thanks

thanks

:)