You do have a backup file that is a bit over 200 mb, files larger then 10 mb are periodically removed (guaranteed shelf life is 4 hours), and the service is not meant for backup storage.
With that large file removed, you fall below the limit for additional increase
Also, it looks like your subdomain is just a duplicate of your mainsite, which I understand from a development point of view, but in general one would be considered to be a backup of the other as well.