Unable to backup to iCloud with storage available
i have an iPhone 5. Have been receiving a message for some weeks that backup is not possible due to lack of storage. I don't wish to purchase storage. Today I deleted photos and excluded unused apps from iCloud to free up storage. Phone shows 5G of space is available but still can't backup. Help please. Also, how do you permanently delete unwanted apps from the phone and icloud?
iPhone 5, iOS 8