retain after downgrade I-cloud

Dear I cloud users,

A few months ago I downgraded my Icloud account from 50 GB to 5 GB, but today I discover that all my pictures and videos are deleted. Is there a why to retain the lost data.?Apple sent me a mail that all the content on I cloud is being saved for 30 days and after this period all the content will be deleted. I totally forget to save the content on time. I hope there is a way to retain my lost data.

Greetings