Question for you all about handling a closed business with ex

So, as many of you know, ex and I owned a business together that I dissolved in December. We sold all the trucks and trailers, and at the time, I have my ex detailed instructions. He was to remove the license plates off the vehicles. Well, he didn't, and today I got an overdue toll notice from one of the vehicles. Do I let him know?

He was supposed to handle the selling of the vehicles, in that he was supposed to remove the plates so that we would not be held accountable for anything.

Do I let him know? Should I advise him? I have a feeling this will be the first of many notices, and the new owner of the vehicle is still driving around with our plate, and our company logo on the vehicle.

????