Apple iphone ios 10.3.1 (NOT 10.3) iCloud storage problem?

I had ios 10.2.something.ICloud backup off and its storage is 0 kb.Updated to ios 10.3.1 today.Found iCloud storage " used (around) 50 kb of 50 gb "
Don't know what info on my phone ware leaked to my iCloud storage.So tried deleting what ever went there by fwllowing there support instructions. But can't see the button that delete's what's there. For over 2hours. I even tried turning on & off iCloud backup. But i didn't even see the pop-up that should ask about turnoff and delete iCloud storage usage. How ever it increased the data in iCloud to 84 kb… My "iCloud drive" & "iCloud backup" are turned off since the day i got this iPhone. But "find my iPhone" is on.Is that little kb's of data on iCloud from "find my iPhone" app? If so can't it be deleted? If its not from this app then how do i delete it? ICloud system won't recognize it cuz its so small data?

How does my Instagram keep getting hacked?

These past few days my Instagram account has been getting hacked and stolen by some Russian email address. Because they keep changing the email address to a russian one. Two times already I have reversed it and gotten it back. Even after the first time enabling two-step verification.

How does this keep happening? I have changed my passwords. Unless it's some kind of virus but I scanned my desktop computer, and thats the only PC I ever logged into it with, is it possible my iPhone has a virus on it? It's fairly new, like a month old and I haven't downloaded any unauthorized stuff, actually haven't downloaded a whole lot yet.