ROBOCOPY - Copy folders content to a single folder

Here is some code I made :)

@echo off
set source="R:\Contracts\"
set destination="R:\Contracts\Sites\"
ROBOCOPY %source% %destination% *.srt *.pdf *.mp4 *.jpg /COPYALL /R:0 /S
for /r %source in (*) do @copy "%destination" .

R:\Contracts\ is full of folders which have files in them.

I want to copy all to R:\Contracts\Sites\ and flatten the folder structure.

Everything copies well but also the folder structure.

Thank you