Hi--
I just checked and I had no problem saving a file to the cloud and opening it up from the cloud. I'm using OS X 10.9.4.
I had previously signed up for various betas for Mathematica On-line, etc. so there may be a set -up issue. I was able to open a file I had saved with the on-line beta some months ago.
I would make sure that your Wolfram ID is being used to set up the cloud, and perhaps sign up for the beta for Mathematica on-line. (I don't know how to do that right now -- it may be by invitation only.) A call to supper (or sales) might help.
The good news is that the functionality seems to be working fine. The only problem seems to be set up.
