The article doesn't really tell us what the contract terms are, though. Just because the city voted to cancel the contract doesn't mean it ends immediately and Flock has to come remove all the cameras upon request. It's very likely the contract has a fixed term, and cancellation really just means they're not going to renew it at the end of the term. If that's the case, you can't charge them with crimes for using infrastructure that the contract permits them to use.
Still terrible that Flock isn't responding to them, and of course even if they intend to hold the city to the contract in terms of expecting to be paid for the full duration, they should still honor the request to shut off service.
One week to respond to a letter delivered by US postal mail isn't really much time. Not that I support Flock or the concept of Flock-style public cameras, but I don't think you can judge them to be "not responding" that quickly.
The political grandstanding will continue at least through the end of midterm season and realistically we're just getting geared up for 2028.
If nothing else, this is a good example of why the contract terms for government vendors MUST be public records and NDAs of private companies on public officials for the purposes of sales should not be legally enforceable.
The first thing the city should do when cancelling is lock down the data so no jurisdictions have access to the data. Even if the cameras are still powered on and connected, any ongoing searches should not return any results from that jurisdiction.