I do sympathize your situation.
However, there are many aspect that you need to consider.
Even though the image is clearly used by AVIS, however, most big company has their marketing such as advert subcontracted to outside resources.
Typically, they are protected against any claim as the sub con will be liable in this case (assuming that they are using one) and that's probably why they don't reply to your email as it is not their "issue".
So the best way to go around it is you will need to email them who is responsible for the online advert campaign for this particular advert before taking any action.
If you need to sue someone, you need to sue the right people.
Second issue is to really if you want to sue them, is to build a case on how much they actually benefit from this advert... (they might not make anything) so you can't really sue if there isn't much benefit to you in the sense.
Regardless of what you want to do, it is still poorly reflected on how business just pick up someone's pictures and use it without any consent. I do feel artist being rip off all the time, especially for those of us who depends on images that we created for a living.
Most of the time, I would just let it go because it takes too much resources (both time and money) to build a case and it is not worth it. It has happen to me many times but guess my main analogy is, if the picture is good enough to be steal and can be steal, it is still partly my fault not to control it enough and perhaps, you ought to pat yourself at the back and say well done.
Another way if you want to do this if you really want to pursue, is to contact the watch manufacturer and let them know the infringrment from AVIS against their product and let them take action.
Chill down and think what you want to do.
You can't act in emotional way in dealing with this as it won't help you think clearly.
Good luck and hey.. Well done! For producing great image that people want to steal.
Regards,
Hart
