Lack of storage when I have over 40gb of data to use.

Hi

I have an iPhone 6 S. I’m. Fairly EE to iPhones as this is my first but so far , not good. I pay 75p per month for an extra 50gb (roughly I think) of data. I have a lot of my images and WhatsApp info backed up but here’s where it gets confusing (see attached photo)

I have so much memory left to use but my WhatsApp and iPhone keeps telling me I have very little data left, which makes no sense to me. My WhatsApp and photos are saved onto the cloud. I don’t even have that many photos yet I am constantly being urged to delete photos, videos and apps to create more space. I recently backed up my WhatsApp. I want to be able to have more than a few apps and I thought buying the extra data would help, but it isn’t. Why isn’t my phone putting the other apps onto the feee storage?

I am also unable to upload some photos onto other apps like snapchat as I think they aren’t the original photos (the ! In the circle I googled and said it’s all stored on my cloud)

but I want the originals on my phone so I can share and they are the original quality. I’m very confused. My photos and WhatsApp are turned on to use my iCloud data but I have so much data left it isn’t using , can someone explain why this is and tell me how to change that? I don’t understand why it’s like this or why I am paying for something that clearly isn’t working. Any info will be really appreciated as I don’t want to go into shops at the monent!