Someone keeps changing my account address and purchasing apps!!!

I don't know what to do. Yesterday morning (about 4am) I get an email showing that I purchased some random Asian apps....except I didn't and so I dig further and notice that someone has changed my address. They kept the same street address from changed my state, city and zip code....to Ohio. I freak out and check my bank accounts, but nothing has been charged. I go ahead and change everything back and change my apple ID password too and I think it's over. Nope, fast forward to tonight (around 2am) and I get another email saying more Asian apps have been purchased except this time it's over $40! The address was changed again to Ohio. Luckily the apps were charged to a credit ending in a number I don't recognize.

I just don't get it.....help?