Deleting a purchased song altogether.

[Dean.]

Hi, ive look on the internet and i cant find the answer

Basically i want to delete the songs i got free in that '12 days of christmas' from my itunes, but becasue i 'purchased' them on my ipad they just keep getting readded whenever the ipad syncs?

I've tried deleting from the ipad, itunes,purchased list and they just keep getting re-added and its so frustrating because i have my itunes in 'date added' order.

Please help. Im rubbish with computers