a DMCA is effective only if you have proofs that you are the author of a piece of work. if you are just a client who paid for a style, which can be a situation, you can report the thief, but no legal action can be taken in your name, because you have to be the owner of the copyright... and actually, in the next weeks/months, the legislation in the US and Canada are about to change because a lot of supposed owners are reporting copyright infrigements that are not even related to them, they are suspicion facts which cause legal problems more than anything... in Canada, you will now have to proove your ownership before taking any action... (that's what occured with me last autumn when someone sued me for copyright infrigements on something i was the right owner...)