Personally, I have not seen this issue as I am not always online.
Try this:
Update your SW (if you have not done that yet http://us.playstation.com/support/systemupdates/ps3/)
Turn off your source of internet (Cable Modem, ATT modem, etc...)
Turn off your router (if you have additional router)
Create a new SSID (if you have the capability of creating a new dedicated SSID for your playstation. If not, no big deal)
Turn off your PS3.
Wait about a minute or so, then turn the PS3 again.
Go to setting and "Test your connection"
Once the testing is complete, open your BF4 app, and see if you are able to get into Multiplayer features.
In regards to saved data, this is what I found on the web. http://www.ign.com/articles/2014/01/21/ps4-error-corrupting-save-files. Most people thought it was BF4 causing it, but in actually, it was the Playstation. (by the way, according to reports, this is still happening after the Playstation update. I lost all my saved data (for Campaign) several times, and I have not gone back since. Having fun enjoying the Multiplayer features.
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