Even r esetting the entire phone doesnt help! help dudes!

Hi guys, the problem which is occurring on my samsung galaxy s2 is a weird one. Every time i switch off my phone, it seems to reset to a certain date, as in, the texts i receive today are gone, new things on games are gone like high scores, and when i delete an app, when i switch my phone off, it reappears, same with videos. I have tried to reboot and reset the phone itself also, and the same thing occurs, i have tried to wipe everything off but nothing happens. Any advice or help here would be greatly appreciated! thanks.