I'm not and have never been in your situation but consider this a summary of all anecdotes I've heard mixed with negotiation techniques.

The thing I would personally do is make sure the client has paid their invoice before providing the service. Essentially, this means paying for all previous missed invoices along with the next one. If you make people pay before giving the service, I think you avoid the case altogether.

Now, if you want to be harder: just ban them. Take them to Collections (or whatever the name is in the USA) and then never provide services to them ever again. This sounds really harsh and unfair but by not paying they also know how far they can go without giving you a dime. "Give them a hand and they take the arm."

upfront billing of professional services (“consulting”) is worse for a few reasons, (1) requires the customer to trust you more (they cannot withhold payment if you screw them or violate the contract) but generally the service provider is the riskier party (2) it causes service gaps (lost billable days) when the customer is late which is almost every month, (3) it requires you to define in advance exactly how many units will be billed and causes a service gap when you hit the retainer limit, (4) it gives the customer a natural ability to throttle billable hours which leads to unpredictable revenue. This all leads to higher bill rates, which is less palatable than a commitment to full time services contract. everyone involved wants predictable spend.

if this is an annual renewal payment for a saas, you need a process to follow which must include 60 and 30 day notices before the invoice, the rest varies greatly based on size - is this $1200/yr (credit card auto charge) or $120k (high touch sales rep)