Permanently delete files on my cloud home

Hi,

“my cloud” app lauched 2 times the iphone back up and saved the pictures/movies under the folder created for that.

So I deleted the folder to back everything up again and have only 1 copy of each file in a new folder.

Problem: the pictures and movies appear now 3 times in the general collection and take a lot of space. Where can i permanentely delete these files?!

Thank you for your help,
Julien