Iphone 4 confusion (itunes)?

Basically hi guys, i've had an iphone for a bit of time and i put my music and everything on my phone through i tunes on my computer without any trouble, and recently i have tried to put new songs on my phone through itunes on the computer. I pugged it in and it was fine, but then it wiped all of my music and added 881 songs on my phone that i don't know where came from so i have deleted the 881 songs and i have no music, and it also deleted my apple id and put on someone's who i don't know, it says the email address and that i need the password to download them but i don't know who's email it is! It is noone in my families and it is really annoying i have no music to keep me entertained and it won't let me download apps! If noone can help me on the weekend ll have to go to barrys phones for you shop and try and get it sorted, anyone who can help gets five stars as best answer!

That's a very strange problem you have. The only thing I can think of is to restore from a back up. You can check when your last back up was if you go to iTunes > Preferences > Devices, if its not too long ago then I think thats the best way forward so at least you can get back to how it was before.

Here's a tutorial on how to restore in case you don't know how to: http://support.apple.com/.../kb/ht1766