Hello Micky3351,
Thanks for the question, and welcome to Apple Support Communities.
I understand that you are having issues backing up your previous iPhone. From your description, it sounds like you are using iCloud to back up. The following article outlines iCloud storage in relation to backups:
iCloud: Managing your iCloud storage
http://support.apple.com/kb/HT4847
Remember that you can also backup and restore your iPhone with iTunes on a computer:
iTunes: About iOS backups
http://support.apple.com/kb/HT4946
For additional information, see the following:
iCloud: Understanding Backup alert messages
http://support.apple.com/kb/TS4576
iOS: Transferring information from your current iPhone, iPad, or iPod touch to a new device
http://support.apple.com/kb/HT2109
Thanks,
Matt M.