iPhone 7 won't back up to iCloud

My iPhone 7 has stopped automatically backing up to iCloud. i got a pop up telling me it's been backing up in ?? days. I know it was doing these iCloud back ups successfully everyday because I checked it a few times. I have tried for days to manually back it up to iCloud it will start but gets stuck about a quarter of the way (states different times ie: estimated time 7 hours or 14 hours or 4 hours) and does not give me an error message or nothing. I have deleted all prior iCloud back ups because in all the research that was always suggested. Now I have Zero iCloud back ups. It states Never. I have backed it up in iTunes with no problem. I paid for extra storage above the 5GB and have done that for quite sometime. I did check however and I have 36GB available of 50GB and my back up size is estimated at 3GB & it Won' t Go. I have signed in & out of iCloud, hard reset phone, even as far as resetting the whole stinking phone and restoring it from my recent iTunes back up. It still is stuck at 6hours with no iCloud backup. Is anyone else having this issue? If so please advise ???? TIA