The reason you see a person’s name and all their entities listed in a lawsuit is because Plaintiff (the suing party) attorneys have to list everyone and every entity that can be remotely tied to a cause of action, otherwise, if enough time passes and through the legal process discover that a separate entity or just a person was truly liable and they didn’t name them in the lawsuit, they are out of luck.

Referring you to COGO's legal team for legal action!

I recommend you decide, take action, and move on. 

Let’s make 2025 a year of action and success!

You could also go work as a buyers agent on a top producers team and do closings that way.

I sold 2 properties that were taking up a lot of my time and were producing very little of my cash flow.2.

There’s normally action items that can be implemented into your management process that are more effective. 

If you're starting with this model, it can be highly beneficial as it allows you to gain first-hand experience with the daily operations, actions that must be taken, requirements, market demands, and more.

What would be the best course of action to sue them for non-payment? 

I'm not sure what leverage you would have outside of taking legal action, these are generally things that should all have been on the closing statment along with deposits etc.