Former employer refusing to pay my expense reports I was promised.

Location: Connecticut, US.

I work and live in CT for a small CT based company. Recently, they called me to tell me I was being let go effective immediately. I lost all access to my computer before I knew what was happening.

On my computer, I had a handful of expense reports that hadn’t been paid out by my company yet. Upon being let go, my company had assured me I would be paid on everything they owed me. These are expenses for trips/tasks requested by my job title, equaling around $12k overall.

I’ve been following up with them, but have been told “we’re not going to pay you as we’ve closed the books on those months”. As someone who is now unemployed, $12k is a lot of money to be denied.

I’m hoping to settle this as civil as possible – they just lost a $3.5M lawsuit for forging documents, and I have a feeling I will have to sue them as well. Can anyone guide me to the best practice here?