Truck Driver Threatening Lawsuit, Broker Exposure, and Public Posts Over Pay Dispute — No Written Contract

I own a small trucking company and I’m dealing with a serious dispute with one of my drivers/owner operators. There was never a written employment contract, but the payment structure was consistently percentage based over multiple loads. Recently the driver received rate confirmations directly from a broker and became upset after seeing the gross broker rate compared to what he was paid.

Now he is threatening lawsuits, public exposure, contacting brokers, posting company information online, and accusing us of altering documents. He also abandoned the truck at a location we did not authorize and used a company-issued BOFA employee debit card for ATM withdrawals that were not pre-approved.

At the same time, there were issues on his side as well including canceled loads, communication problems, and operational disruptions that caused broker complaints and even a FreightGuard report against the company.

We are trying to settle the dispute professionally with a written settlement agreement and payment offer, but he continues threatening escalation if not paid immediately.

My questions are:

1. How serious is this legally from a civil standpoint?
2. Does repeated acceptance of the same percentage-based payment structure matter legally?
3. If there was no written contract, what generally controls in situations like this?
4. What is the best way to protect the company moving forward?

Location: Florida