Apple acount hacked?

Hello,

I have a problem since a few days: I can’t buy any new app.

When I try, I have the message: « please verify your payment information », and something about a problem of billing with an earlier purchase. When I follow the link, it shows me the credit card used to do this earlier purchase... But it’s not mine! But somehow, the purchase was made with my account... and as the credit card used isn’t valid, I am suspended from bying anything.

I did try to enter MY credit card in my settings (which I already did before), but it says that the security code is invalid.

Also, my account seems to be part of an « icloud family » now.

What can I do?