You might need to delete your save data if it keeps erasing itself. I know it sucks loosing your stuff but try to get your hands on an all items world and hopefully restore your progress.
Yikes. I think I'll leave that step for last though if it comes to it. I'm currently bypassing the mysterious disappearances with the seemingly working cloud saves and playing sparingly on a temporary world.
Plus I'm stubborn as a mule. I refuse to lose my stuff. Hahaha.
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[Update 4]
1 week later... the saves haven't returned. However, I went on player 2 and checked their save data and the memory is 6300~ Kb (6Mb). That save has 4/5 characters (most are well armed) and 3/8 Worlds (just empty ones). Comparing to player 1 data (4/5 Characters, 2 empty ones and 6/8 worlds, 3 mostly unaltered and currently an additional world mostly unaltered to pass the time) which is sitting at 12Mb up from 10Mb (maybe cause I saved in the new world)... The memory usage and storage is true I guess; as I play player 1 more and usually solo plus player 1's worlds are more loaded with items and structures. This does not match up as player 1 LOST EVERYTHING. This should've dropped the memory down to <750Kb if it were truly wiped (as player 1 was left with only 1/5 characters and that was it). This obviously doesn't make sense.
Not to forget the mysterious vanishings of newly created worlds and characters, which makes this problem even more odd. Again, no sense whatsoever.
This makes me believe that the data is still there, but for some reason are gone or aren't showing up. I have also been playing for the past 3-4 months up until the patch... there could be a bug in the patch that they haven't caught, which makes the way the game handles your data messed up. I mean looking back in time; 505 games had to release a patch that restored certain "corrupted" saves, but only if you haven't saved over the original data (EDIT1-This was said by a forum goer in the terrariaonline forums, but I can't access the information).
Contact with 505 games and Engine software have ceased (no more addition responses or returned responses).
However the message I sent now varies in accuracy as I learn more about this problem. Hopefully they care and look at the forums.
Other then that I feel more hopeful and plan to wait in the mean time until the answer is more definite. I'll continue to update as I see fits or stop without warning.
EDIT1- Here are the additional sources (can't seem to find the other ones or access them). It was all I can get within 10 minutes.
http://www.playstationlifestyle.net...es-within-terraria-patch-1-2-is-in-the-works/
http://www.gamefaqs.com/boards/709410-terraria/69047252