My Cloud uses storage space In my iPhone

I bought the My Cloud storage so I can free space in my IPhone but the app is using up to 2 Gb of storage space in my device. This is ridiculous! I already set the cache to the minimum value and cleared the cache several times In the app and it still uses almost 2 Gb.
Furthermore I can’t setup the WD My Cloud in my Macbook so I can use it as Time Machine. My Mac does not recognize the My Cloud even if it is available in finder. My device does not have the 9 digit code requested and WD’s helpdesk answers didn’t solve any problem.
I’m having a truly unpleasant experience with this device. Starting to regret my decision to buy it.
Can anyone help me?

Relax Pal, it is not the fault of the my cloud. Have you looked in to the user manual?

The my cloud device does not use any storage in the iPhone. The my cloud app does if you downloaded any files to it. You have to delete downloads when done. The mobile app’s cache only reserves space in app for media you play. In app Settings click on HELP