What’s going on with these ringtones?

Two months ago, my Optus bill included a charge for twenty bucks for ringtones downloads from Motorola. I meant to query it but forgot. Then this month there was a charge of sixty bucks for more ringtones from Motorola. I complained and Optus credited my account for the full eighty bucks. But after many phone calls, I still can’t find out how I got billed for all those ringtones when I’ve never registered with the Motorola website, never requested any ringtones and never received any. I wonder whether I was just unlucky. Has this happened to anyone else? And, remember, check those mobile phones carefully.