Private towing of 18 wheelers on private property?

Hi all. My husbands father owns some land, about 3 acres worth. He was served a note by the city to remove all the vehicles (he was using the land to park 18 wheelers of people that paid him and it was unauthorized).

That was several months ago. There are a few remaining 18 wheelers that are obviously abandoned. Flat tires, plants growing around and out, etc.

Is there someone we can call to tow these without us having to pay? The people were given notice/refused to even answer over 6 months ago.

My FIL has a followup from the city coming and we want these trucks gone ASAP without having to come out of pocket for other people’s ignorance.