You should absolutely report it to the FCC. It’s unlikely they even know it’s happening and regardless it’s illegal. Whoever maintains the equipment ought to know better and correct the problem. If it’s broadband interference it’s not likely to be limited just to those you’re using. There’s something very wrong with their system.

Source: I’m an Extra-class licensed amateur operator. I’ve reported improper interference from “official” systems and gotten results quickly using basic logs.

Adding note: I’m not an expert on trunking systems but understand the basics. Unless your business shares the trunking system with the local police (unlikely given the age of your system and that you specifically mention the encrypted / maybe just digital system they’re now using), you shouldn’t be sharing the same set of frequencies. If you were on the same system, you’d have “talk groups”, and if your radio is configured to hear all groups instead of yours, you’d hear their traffic. Our city/county system shares a trunk system among all kinds of city services, using talk groups. I think there’s a business or two that leases space but I can’t remember, so it’s not impossible for a business to lease space on a shared county system. In that case either their radios are misconfigured vis-a-vis proper talk groups or yours is. Maybe both? 😂